METALLURGICAL A B ST R A C T S
(G E N E R A L A N D N O N -F E R R O U S )
Y o lu m e 3 J U L Y 1 9 3 6 P a r t 7
I.— P R O P E R T IE S O F M ETALS
(C o n tln u ed fro m p p . 103-197.)
*Colloid Chemical Phenom ena in M etals. I.— Gases in A lum inium . J . A.
K liachko (K olloul-Zeit., 1935,73, (11), 2 2 6 -2 3 6 ; a n d (sum m ary) L ight M etals Research, 1935, 4, (19), 3 1 4 -3 1 6 ; Sci. A b s., 1936, [A], 39, 9).—T h e system g as-m eta l is stu d ie d as a problem in colloid chem istry. T ho g enerał law s w hich are v alid fo r a g a s -m e ta l sy stem a re briefly sum m arized, follow cd by a d escription of re su lts of earlier w orkers o n th e in te ra c tio n of gas a n d alum inium a n d its alloys. T h e a m o u n t of gas w hich dissolves in alum inium (chiefly hydrogen) dillers according to w h e th e r th e d e term in atio n is m ade by analysis a fte r e x tra c tio n b y h e a t o r b y th o e ąu ilib riu m m eth o d . Sug- gestions are m ado to acc o u n t fo r th is discrepancy. T h e origin of th e gas is shown to be d u e to th e re a c tio n betw een th e m e ta l a n d th e w a te r v a p o u r adsorbed in its pores.— S. G.
Study of the M anufacture, Properties, and Uses of Refined A lum inium . R o b e rt G adcau (Congris internat. M in e s M et. G iol., Section de M ktallurgie, 1935, 1, 8 5 -9 0 ; a n d J . Four Łlect., 1936, 45, (1), 17-22).— [ I n F re n c h .] See M et. Al>s., th is vol., p . 69.— S. G.
* 0 n the Atom ie W eight of Cadmium. O. H o nigschm id a n d R . Schlee (Z.
anorg. Chem., 1936, 227, (2), 184-192).— A nalysis of th e b rom ide a n d chloride ob tain ed from m e ta l w hich h a d been fra c tio n a lly d istille d in ra m o g av e th e value Cd = 112-41.—A. R . P .
*On the Passivity o£ Chrom ium . IV .—The E lectrolytic B ehaviour of Chrom ium A m algam . E ric h M uller (Z. physikąl. Chem., 1936, [A], 176, (4), 273-288).
—C om pact chrom ium rem ain s p e rm a n e n tly activ e in iI/-h y d ro ch lo ric a c id a t 20° C., b u t chrom ium am alg am u n d e r th e sam e co n d itio n s undergoes a con- tinuous cycle of changes from th e activ e to th e passivo co n d itio n a lte rn a te ly . B o th th e co m p ac t m e ta l a n d th o am alg am a re n o rm ally passive in Jf-su lp h u ric an d il/-perchlorio acid s, b u t th e fo rm er can be m ad e p e rm a n e n tly a n d th e la tte r tra n sie n tly a e tiv e by feeble cath o d ic po larizatio n . T ho am alg am can be rendered active in A f-sulphuric a c id m erely by sh ak in g , a n d th e r e tu rn to th e passive State is accom panied by periodic v a ria tio n s, a phenom enon w hich is n o t obscrved w ith chrom ium pow der. S tro n g cath o d ic p o la riz a tio n ren d ers th e am algam passive in a ll th re e acids ; th e a e tiv a tio n p o te n tia l is low er fo r th e am algam th a n fo r th e co m p ac t m etal.— B . BI.
T herm o-E .m .f., P eltier Effect, an d P h oto-E .m .f. in the Celi Copper-Cuprous Oxide-Copper. G. M onch (Z. tech. P h y sik , 1935, 16, (11), 361-363).— See M et.
Abs., th is vol., p. 31.—J . S. G. T .
*Peltier Effect in the E lem ent Copper-Cuprous Oxide-Copper. G. M onch (Z.
Physik, 1936,100, (5/6), 321-325).—Cf. a b s tra c t above. T he P e ltie r effect a t a copper-cuprous oxide in terface, is, in accordance w ith th e o ry , fo u n d expcri- m entally to be p ro p o rtio n al to th e ab so lu te te m p e ra tu re of th e in terface.— J . T.
The Properties and Uses of Lead. R . S. R ussell (M et. In d . (Lond.), 1936, 48, (21), 585-590).—F ro m a series of artic le s in M o d em E nejineer; secM et.A b s., th is yo1„ p . 193.— J . E . N .
*The Effect of Absorbed H ydrogen on th e M agnetic Susceptibiiity of M an- ganese. M ary A. W heeler (Phys. R ev., 1936, [ii], 49, (8), 642).— A b s tra c t of a
* Denotes a paper describing th e results of original research.
t Denotes a lirst-elasa critical review.
S
238 M etallurgical Abstracts
V o l . 3 p ap er read. boforc tho A m orican P h y sical Society. M anganese w hich h a d been purified b y d istillatio n w as h eate d in h ydrogen a t v arious te m p e ra tu re s. T h e su scep tib ility a t room te m p e ra tu re w as deereased to 9-2S( 10)_c from a norm al valuo of 9-60(10)-° w hen th e ab sorption to o k place a t 400° C., a te m p e ra tu re a t w hich th e a form is stable. W hen th o h ydrogen was absorbed in th e [3 form a t 850° C. th e susceptibility becam e 9-36(10)-°. T he deereased su scep tib ility c an be d u e to th e ad sorption of diam agnetic hydrogen. W hen th e h ydrogen w as absorbed b y th e y form a t 1220° C. o r by th e m elted m anganese, how ever, tho su scep tib ility w as inereased to 10-42(10)"° a n d 10-00(10)-®. W hile a- a n d P-m anganese havo com plicated stru ctu res, y-m anganese is a sim ple face-centred te tra g o n a l form . T h u s in y-m anganese th e hydrogen is p ro b a b ly in serted in to rstitially a n d inereases th e la ttic e co n stan t. T h is could cause a narrow ing of th e energy bands of tho eollective eleetrons an d a n increase of th o su scep tib ility . N o traco of ferrom agnetism w as found.— S. G.
♦Absorption of Gases by M ercury. S. P tiz in (Tech. P hysics U .S .S .R ., 1935, 2, (1), 6 6 -7 8 ; S ci. A bs., 1936, [A], 39, 25).—-[In English.] T h e a b so rp tio n of gases, w liether air o r organie yap o u rs, is stu d ied , a n d th o ąu estio n of freeing m ercury from absorbed gases is also d e a lt w ith. H y d ro g en distilled in a vacuutn gives off b u t little air, 130 m m .3 of m ercu ry giving off only 0-5 m m .3 of gas m easured a t 1 m m . pressure, even a fte r being sto red fo r som e tim e open to th e air, while cleaned m ercury only absorbs atm ospheric gases fo r a few lirs.
I t w as also shown t h a t m uch of tho gas lib erated com es from th e decom position of organie com pounds absorbed in th e m ercury.—S. G.
*The D ensity of M ercury a t 0°. T . B atuccas a n d F .-L . Casado (J. chim . phys., 1936, 33, 4 1 -5 0 ; C. A b s., 1936, 30, 3287).—A b o u t 29 kg. of carefully purified m ercury from S pain w as used. T h e d en sity a t 0° w as d eterm in ed by th e pycnom eter m ethod. T he average of 22 d eterm in atio n s w as d\ = 13-59539
± 0-00001 g rm ./m l.— S. G.
♦The Diffusion of Gases Through Metals. H I.—The Degassing of N iekel and the Diffusion of Carbon Monoxide Through Niekel. C. J . S m ith ells a n d C. E . R an sley (Proc. Iloy. Soc., 1936, [A], 155, (8S4), 195-212).— A p a rt from easily d etach ab le surface gas, th e gas cvolvcd from com m ercial n iek el b y h e a tin g in m eno o r in hydrogen is m ainly c arb o n m onoxide. T h e m easu red ra to of diffusion of th e gas is fa r too sm ali to acco u n t fo r th o ra to a t w hich gas is evolved from tho m e ta l in th e u su al degassing processes. I t is suggested t h a t th e carbon m onoxide is g en erated from uncom bined c arb o n a n d oxygen con- ta in e d in th e m etal. E x p erim en ts su p p o rtin g th is h y p o th esis a re described, a n d i t is likely t h a t tho ra to of evolution of carbon m onoxide is co n tro lled by th e ra to of diffusion of carb o n in th e m etal.— J . S. G. T .
Note on the Curie Point o£ Niekel. E d m u n d C. S to n e r (Proc. Leeds P h il.
L it. Soc., 1936, 3, (3), 127-131).— Tho conventional Curie p o in t is red u ced from th e resu lts of W eiss a n d F o rre r fo r niekel. T he valu e of 0 (in ° C.) o b tain ed by ex trap o latio n of th e steep est p a r t of tlie o, T curve is given closely by 0 = 361-5 + 1-6 X 10~3 H . E x tra p o la tio n of th o steep est p a r t of tlie a a~, T curve giyes approxim ately 0 = 357-5 + 0-8 X 10"3 I I . T h e form of th e cr0, T curve giying th e yariatio n w ith te m p e ra tu re of th e intrinsic m ag n etizatio n in zero field (deduced b y oxtrapolation, using th e m agneto-ealoric resu lts) is discussed. I t is show n t h a t th e experim ental re su lts do n o t enable a u n iq u e Curie tem p eratu re to be deduced such as is in d icated b y th e idealised th eo ry . S. em phasizes th e need fo r indicating clearly th e m eth o d u sed in deducing Curie tem p eratu res w hen theso are given on th e basis of ex p erim en tal r e s u lts ; p a rtie u la rly in connection w ith possible differenees in th e Curie te m p e ra tu re s of m aterials of n early th e sam e com position.— S. G.
♦The In te m a l E nergy of Ferrom agnetics [M agnetic Constants (and Specific H eat) of Niekel]. E d m u n d C. S to n er (Pliil. Trans. R oy. Soc., 1936, [A], 235, (750), 165-193).—T heoretical. E stim a te s of th e specific m o lecu lar field coeff.
1 9 3 6
1.— Properties o f M etals 239
N p for forrom agnctics (N — th e fo rm al m olecular field eocff., p = th e den sity ) differ w idely n o t on ly fo r d ifie re n t te m p e ra tu re s b u t fo r th e sam o te m p e ra tu ro w hen d erived from d ifferen t sets of d a ta . A d o tailed e s a m in a tio n is m ad e of tho ex p erim en tal re su lts fo r th o m ag n etizatio n , m agneto-oaloric offcct, a n d specific h e a t of nickel, a n d th e assu m p tio n s of th o calcu latio n s b y th e d ifferen t m ethods are discussed. Tlie re su lts as a w hole in d ic a te v alu es of N p , n o t v arj'in g ap p reciab ly w ith tlie specific (in trin sic) m a g n etizatio n c , of a b o u t 11-7 x 10* above 500° C., a n d n o t less th a n 9-5 X 104 a n d 7-4 X 104 a t 350° C.
a n d room te m p e ra tu re , respectively. E v id en ce is given fo r th e oxistence of a m agnetic “ d o m a in ’! s tru c tu re . T h is u su a lly corresponds w ith th e m osaic s tru c tu re of m etals, b u t m ay som etim es be d is tin c t a n d e ith e r la rg e r o r sm allcr.
— W . H .-R .
♦The Change of M agnetization of Nickel, Perm alloy, an d Nickel Single Crystals in Strong Fields. G ord G erloll (Z. P h ysik, 1936, 99, (9/10), 585-594).—T h e m agnetic su seep tib ility of nick el a n d of P erm allo y a tta in s , a t room te m p e ra tu re, a c o n s ta n t yalue in fields of stre n g th a b o u t 40 0 0 O ersted t, a n d th is yalue changes b y less th a n 6% fo r fields of s tre n g th u p to 5500 O ersted t.— J . S. G. T .
♦The Freezing P o in t of Palladium . F . I I . Scliofield (Proc. B oy. Soc., 1936, [A], 155, (885), 301-308).— T he freezing p o in t of p a lla d iu m , d ete rm in e d from m easurem ents of b rig h tn ess ra tio , fo r a c e rta in w avc-length of black body rad iato rs held a t th e freezing p o in ts of p a lla d iu m a n d gold, is fou n d to be 1554-4° ± 1° C. o n th o In te rn a tio n a l T e m p e ra tu re Scalę. T h e valuo recom - m ended in th o specification of th a t scalo is 1555° C.—J . S. G. T .
*Param agnetism of P la tin u m Colloidal Pow ders. N oboro T a k a to ri (K inzoku no K en kyu (J. S tu d y M etals), 1936,13, (5), 161-172).— [In Ja p a n e se .] M easure- m ents w ero m ad e of th o p ara m a g n e tie su scep tib ilities of p la tin u m colloidal particles a n d of those w hich h a d been annoaled a t 800°—1000° C. I t w as fo u n d th a t tho specific su se e p tib ility of p la tin u m colloidal p articles w ith d iam eters of 2-3-10-5 nim . decreases by 21% as com parod w ith those w hich h av e been annealed a n d b y 29% as com pared w ith th e m assivo s ta te . T ho m agnetic suseeptibility of v ery m in u to p la tin u m p articles w hich w ere observable only w ith hig h m agnifieations w as also s t u d ie d ; th e su seep tib ility decreases w ith size.—S. G.
♦Alkali Film s of A tom ie Thiekness on P latinum . H e rb e rt M ayer (Z. lech.
Physik, 1935, 16, (11), 4 5 1 ^ 5 4 ).—See M ci. A b s., th is vol., p . 32.—J . S. G. T .
♦The T heoretical Constitution of M etallie P otassium . E . G orin (P hysikal. Z . Sowjetunion, 1936, 9, (4), 328-344).— [I n E nglish.] A th eo retical discussion of th e co n stitu tio n of m etallie p o tassiu m , b ased on tho thoories of W igner, Seitz, an d H a rtre e , an d on w avo m echanies is p resen ted . T ho finał re s u lts aro th a t th e binding energy a n d la ttic e co n sta n ts arc , respectively, 20-4 kg. cal. a n d 4-80 A., com pared w ith th e ex p e rim e n ta l values 22-6 kg. cal. a n d 5-20 A.— J . S. G. T .
♦The M agnetoehem istry of R h enium : M etallie R henium an d Septivalent Rhenium . N . P e rra k is a n d L. C apatos (P raktika (A kad. A thenon), 1934, 9, 121-125 ; O. A b s., 1936, 30, 3289).— [I n G reek.] Cf. M et. A b s., 1934, 1, 551.
Metallie rhenium a n d th o so p tiv a le n t com pounds of th e elem ent, viz. R e 20 7, K ile O.,, N H .,R e0 4, wero stu d ie d fo r p aram ag n etism . S e p tiv a le n t rh en iu m possesses a p aram ag n etism in d ep en d e n t of tho te m p eratu ro , y_ = 0-04 X 10"°
per grm . as com pared w ith 0-046 X 10~e fo r m etallie rh en iu m , a n d 0-04 X 10-0 for osm ium . R ed u ctio n w ith h ydrogen gives a v c ry p uro rh e n iu m from th e am m onium s a lt, w ith a yalu e of ^ = 0-037 X 10-0 p er g rm .— S. G.
♦The Atom ie W eight of R ubidium . E . II . A rchibald, J . G ilb ert H ooley, a n d N orm an P hillips (J. A m er. Chem. Soc., 1936, 58, (1), 70-72).— R e-investigation of th e atom ie w eight of ru b id iu m b y d e te rm in a tio n of th e silv er-ru b id iu m chloride ra tio gave a slig h tly h ig h er v alu e fo r th is c o n sta n t (85-482) th a n t h a t aceepted b y th e In te rn a tio n a l C om m ittee. Cf. follow ing a b s tra c t.—S. G.
240 M etallurgical Abstracts
V o l . 3*The Atomie W eight of R ubidium . E . H . A rchibald a n d J . G ilb ert H oolcy (J. A m er. C han. Soc., 1930, 58, (4), 618-619).— Cf. preceding a b s tra c t. T he nephelom etric d eterm in atio n of th e ru b id iu m b ro m id c-silv er ratio s gave a v alu e of 85-483 fo r tho atom ie w eight of ru b id iu m a n d th e grav im etric estim a- tio n of tho ratio s ru b id iu m brom id e-silv er brom ide gave 85-478. W h en these values are com bined w ith t h a t o b tain ed from th e ru b id iu m chloride analyses, th e avcrago value 85-481 is obtained.—S. G.
*Germieidal Properties of Silver in W ater. J . J u s t a n d A. Szniolis (•/. A m er.
W ater W orks Assoc., 1936, 28, (4), 492-506).—T h e a d d itio n of silv er to w a te r in am o u n ts betw een 25 an d 600 y p er litre d estro y s b acte ria, m iero fau n a an d m ieroflora, an d aets w ith in a sh o rt tim e on organism s such as d a p h n ia a n d fishes. T h e action is id cn tical w h eth er tlie silver is a d d ed as a soluble s a lt o r is dissolved by electrolysis by th e “ elec tro eatad y n izatio n ” process. T h e a m o u n t of silver dissolved in th is process is show n to dep en d n o t on ly on th o e u rre n t b u t also o n th e m inerał c o n te n t of tho w ater. E x p erim en ts show ed t h a t B . Coli a d d ed to tap -w ater w ere killed w ith in 2 -3 hrs. by a dose of 100 y of silver por litro, b u t t h a t i t retpiircd 5 -7 hrs. w hen th e sam e n u m b e r of B . Coli w ere ad d e d to pollu ted w ater. Pvats fed fo r 100 days w ith w a te r co n tain in g u p to 1000 y of silvcr p e r litre show ed no obvious sym ptom s of poisoning, b u t p ath o - logical changes w ere found in liver, kidney, a n d spleen. C o n sta n t use of w a te r disinfected by silver th u s e a n n o t be considered q u ite innocuous. F o r deter- m ining (w ith a n aecuracy of 2-5 y) sm ali ąu a n titie s of silv er in w a te r, 2 -1 0 d ro p s of 1 :1 hydrochlorie acid a n d 2 d rops of 1 : 10 p o tassiu m iodido are a d d ed to 100 m l., th e solution filtered th ro u g h a m em branę filte rin a K olkw itz filtra tio n a p p a ra tu s, an d th e filter m oistened w ith H 2S w ater. T he disc is d ried a n d its colour com pared w ith sta n d a rd s. A bibliography of 19 roferences is ap p en d ed .
— J . C. C.
*Transition of a M onoerystalline Tin Sphere from the Superconductive into th e Non-Superconductive State. W . J . de H a a s a n d 0 . A. G uinau (Pliysica, 1936, 3, (3), 182-192; a n d K . Onncs Lab. Leiden Comm . N o. 241a ; S c i. A bs., 1936, [A], 39,416).— [I n English.] T he s tu d y of th e p e n e tra tio n of a m agnetic field into a supcrconductive tin cylinder (M et. A bs., 1935,2,277) is e x ten d e d to m onoerystalline spheres, fo r w hich th e d em agnetization fa c to r is know n. A m agnetic field was applied to th e sphere a n d its in te n sity increased a t c o n sta n t tem p eratu ro u n til su p erco n d u ctiv ity w as entiroly d istu rb ed . I t w as eon- cluded th a t th e a p p a re n t perm eability of th e sphere is zero so long as th e applied field s tre n g th is low er th a n $ of th e field w hich d is tu rb s super- oonduetivity entirely. T h e perm eability increases lin early u n til i t reaclies th e value u n ity w hen tho applied field a tta in s its critical valu e. T h e tra n sitio n w as also stu d ied in a c o n sta n t e x tcrn al field w hile th e te m p e ra tu re w as being increased.— S. G.
*The Therm al Conductivity of T ungsten. W a lte r C. M ichels a n d M a rth a Cox (Physics, 1936, 7, (4), 152-155).— T he tlieory of th e h c a t losses from a n electri- cally -h eated w ire, as given by R o b e rts a n d K a n n u lu ik , has been e x ten d e d to include a wiro su p p o rted by springs. T h e re su lts o b ta in e d wero u sed in a m easurem ent of th e th e rm a l co n d u ctiv ity of com m ercial tu n g s te n w ire in tho ran g ę 78'5-273° K . T here are definite in d icatio n s t h a t th e W ie d e m a n n -F ra n z law breaks dow n b ad ly in th is region.—S. G.
♦Therm ionie Em ission from B arium -Coated Tungsten. L . N . D obretzow an d G. A. Morozow (Physikal. Z . Sowjetunion, 1936, 9, (4), 352-361).— [ I n E nglisli.]
T he em ission of oleetrons an d positive ions from tu n g ste n in a stre a m of barium v a p o u r is investigatod. T he em ission of electrons depends on te m p e ra tu ro in th e sam e m an n er as t h a t from tu n g ste n in a lk ali vap o u rs. T h e presence of a po3itive-ion e u rre n t produced b y surface ionization of b a riu m on tu n g s te n is estab lish ed . T he lieat of ev ap o ratio n of b ariu m ato m s from tu n g ste n is found
1 9 3 6
I .— Properties of M etals 241
to bo 151,000 ± 10,000 cal./m ol. for th e range of a c tiv a tio n (as defined by L angm uir) 0 = 0 -3 -0-7 a n d deereases w ith in ereasin g 0.— J . S. G. T.
The Dissociation E nuilibrium of H ydrogen and Its A dsorption on Tungsten.
J . K . R o b e rts (Proc. Cambridge P liil. Soc., 1936, 32, (1), 152-157).-—Tho vario u s processes oeeurring a t th e surface w hen h ydrogen is adsorbed on tu n g ste n aro considered to g e th e r w ith th o dissociation eąu ilib riu m of h y d ro g en in th e gas phase. Tho form of th o a d so rp tio n iso th erm is deduced from th e principle of d etailed balancing, a n d is in ag reem en t w ith t h a t o b tain ed b y F ow ler using a statistical m eth o d . A d etailed in te rp re ta tio n of th e ex p erim en tal resu lts now availablo sliows t h a t e ith e r (a) m easu rem en ts of th e ra to of rem o v al of tho adsorbed film of oxygen on tu n g s te n do n o t m easure th e ra to of ev ap o ratio n of oxygen a to m s ; o r (b) i t is n o t possiblo to o b ta in a g enerał first approxim - atio n form uła giving th e ra te of ev a p o ra tio n of adsorbed ato m s in te rm s of th e heat of desorption. T he d eso rp tio n of hyd ro g en from tu n g s te n is discussed, an d it is show n t h a t th e agreem en t betw een tho te m p e ra tu ro a t w hich tho film evaporates a t a n appreciablc ra to a n d t h a t deduced fro m a d eso rp tio n fo rm u ła of tho ty p e m en tio n ed in (b) assum ing t h a t th e h ydrogen ev ap o rates as ato m s m u st a t p re se n t be reg ard ed as a coincidence.— S. G.
*Ca3sium-Oxygen Film s on Tungsten. J . H . Lees (P hil. M ag., 1936, [vii], 21, (144), 1131-1139).—T ho m ode of fo rm atio n of th e oxygen la y e r is investi- gated, th o oficcts of pressu re, te m p e ra tu ro a n d tim e of a c tiv a tio n , tim e for adsorption being ex am in ed .— J . S. G. T .
*D isintegration of a M onatom ic L ayer of T horium on a T ungsten Cathode in a Mercury D ischarge. N . Morgu lis a n d M. B e m a d in e r (Tech. P liysics U .S .S .R ., 1935, 2, (4), 333-352).— [I n E nglish.]—S. G.
T h e D ependence of Cathode Sputtering on T em perature [Tungsten]. N . D . Morgulis, M. P . B e rn a rd in e r, a n d A. M. P a tio c h a (Pliysikal. Z . Sow jelunion, 1936, 9, (4), 302-316).— [I n G erm an.] I t is show n e x p e rim e n ta lly t h a t th e critical p o te n tia l for th o sp u tte rin g of th o ria te d tu n g s te n b y m ercu ry ions a t 1350°-1750° K . a n d tho a m o u n t of sp u tte rin g of p u re tu n g s te n by m ercu ry ions a t 800°-2000° K . are p ra c tic a łly in d e p e n d e n t of tho anodo te m p e ra tu re .— J . T.
* 0n th e Creep of Zinc. N . N . D av id en k o v a n d I . N . M irolubov (Z hurnal Tehnicheskoy F iz ik i (J . Tech. Pliysics), 1936, 6, (1), 60-77).— [In R u ssian .]
An a p p a ra tu s is described b y m eans o f w hich specim ens o f zinc single cry stals can bo stre tc h e d a t a c o n sta n t ra te o f 5'10"3 m m ./h r. Stress-flow d iag ram s fo r several zinc single cry stals w ere fo u n d to be id e n tic a l w ith thoso o b tain ed a t usual rates, b o th as reg ard s tho lim it o f flow a n d th e occurrence o f discon- tinuities. A n e x p lan a tio n o f th ese d iscontinuities is ad v an ced , a n d th e ir occurrence a t c o n sta n t lo ad is com pared w ith t h a t a t c o n sta n t rato o f deform a
tion.—N . A.
*The Free Energies and V apour Pressures of th e A lkali Metals. A. R . G ordon (•/. Chem. P hysics, 1936, 4, (2), 100-102).— T ho free energies of th e d iato m ic alkali yap o u rs, Iv2, N a 2, a n d L i2 arc calc u lated from speetroscopic d a ta , an d th e eąuilibrium c o n sta n ts fo r th e d isso ciatio n in to th e m o n ato m ic form a re com- p uted. W ith th e a id of th ese c o n sta n ts, ecjuations a re d educed from th e observed v a p o u r p ressures o b ta in e d b y o th e r in v estig ato rs, w hich give th e p artial pressures of ato m s a n d m oleeules in th e sa tu ra te d v ap o u rs fo r te m p e ra tures up to th e n o rm al boiling p o in t. I n th e cases of sodium a n d p o tassiu m th e entropy of th e solid m e ta l is co m p u ted from th e v ap o u r pressure e ą u a tio n , a n d is com pared w ith t h a t p re d ie te d b y th e th ir d law of th erm o d y n am ics.— S. G.
The A tom ie Fregueneies of the A lkali M etals. B in a y e n d ra N a tli Sen (Gazz.
chim. Hal., 1935, 65, 907-908 ; C. A b s., 1936, 30, 3288).— T h e fo rm u ła of S. fo r calculating th o v ib ra tio n freąuencies of ato m s ( c f ../. In d ia n Chem. Soc., 1934, 11,243) gave resu lts close to tlie ex p crim en tal values a n d to thoso o b ta in e d b y oth er form uła;, ex cep t fo r s u lp h u r a n d selenium . T h is m ig h t bc ex p lain ed b y th e allotropy of su lp h u r a n d selenium o r b y th e ir p h o to electrie p ro p ertie s, especially
242 M etallurgical Abstracts
V o l . 3 w ith selenium . C orresponding calculations w ith th e new fo rm u ła of o th e r elem ents w ith photooleetric p ro p erties, viz. sodium , p o tassiu m , lith iu m , ru b id iu m , an d oresium, give re su lts w hieli agree w ith those o b ta in e d b y o th e r form uła! (esoopt for lith iu m ). A ceordingly th e diseordances in th e c alc u lated ato m ie freąuencies of selenium an d su lp h u r a re a ttrib u ta b le to th e ir allo tro p y ra th o r th a n to th e ir photooleetric p ro p ertie s, w hich su lp h u r possesses to an in sig n ifican t degree.—S. G.♦Photo-Effecfcs of T hin Adsorbed Film s of the A lkali M etals. V. G ey a n d J . T ru te ń (Zhurnal elcsperimentalnoy i teoreticheskoy F iz ik i (J. E xp er. and Theoret. P hysics), 1936, 6, (1), 30-36).— [I n R u ssian .] B y ad so rp tio n of th e v a p o u rs of alk ali m etals, films w ith a thiekness of seyeral ato m ie layers h ave b een o b tain ed . T he electrical co n d u ctiv ity of th ese films obeys O hm s’ law . Tho relativ o p h o to -c u rre n t curves o b tain ed from th em do n o t re v e a l selectivc m ax im a.—-N. A.
U ltim ate Strength of M etals. E . N . d a C. A ndrado (Science Progress, 1936, 30, (120), 5 9 3-610; C. A bs., 1936, 30, 3757).—A eonsideration of tlie fuijda- m e n ta l problem s of m etallie s tre n g th an d of yield u n d e r stress, w ith 28 refer- ences.—S . G.
F irst R eport on Viseosity and Plasticity. C om m ittco fo r th e S tu d y of V iscosity of th o A oadcm y of Sciences, A m sterdam ( Yerhandel. A ka d . Wet.
Amsterdam-, Afdeel. N atuurkunde, l s t Sect., 1935, 15, (3), 256 p p . ; C. A bs., 1936,30,3692).—Tho basie m echanical relations, th e exp crim cn tal investigation of flow p ro p erties, th e m easurem ent of viscosity, viscosity an d p lasticity from a tech n ical p o in t of view, th o p la s tic ity of m etals a n d o th e r crystallino sub- stances, &c., are discussed.—S. G.
The D eform ation, Reeovery, and R ecrystallization B ehaviour of M etals.
R . H . H obrock (./. A eronaut. S ci., 1936, 3, (6), 191-199).—T he b eh av io u r of singlo-crystal stru c tu re s und o r m echanical stress is c o n traste d w ith t h a t of tho finely polycrystalline m a te ria ls in o rd in a ry tech n ical iiso. “ R ecovery ” from w ork-hardening is d istin g u ish ed from “ tem per-relief,” w hich is defined as a h eatin g a n d cooling o p eratio n in ten d ed to bring tho p ro p ertie s of a n alloy as n ear as possible to those of its p re d o m in atin g m etallie co n stitu en t. T h is can bo elfected w ith o u t achioving “ recovery,” o r th e relief of strosses in th e lattico.
T h e m echanism of grain-grow th is discussed, a n d th e th ree-d im cn sio n al re- c o v o ry -recry stallizatio n d iag ram of a n alloy of th e D u ra lu m in ty p o is re- produced. T h e ann ealin g te m p e ra tu re necessary fo r th e relief of in te rn a l strosses m ay com e w ith in th e re c ry sta lliz a tio n rangę, a n d g rain-grow th m ay th u s be s e t u p : som e m eans of p rev en tio n are suggested.—P . M. C. R .
*The T herm al Stress in a Strip D ue to V ariation o! Tem perature Along the L ength and Through the Thiekness. (G oodier.) Sec p. 278.
*On the Sticking of Two Metal Surfaces to One A nother in a V acuum an d the R eduction of Sticking by Yarious Gases. R a g n a r H olm a n d B e rn h a rd K irschstein (JFiss. Veróff. Siem ens-W erken, 1936,15, (1), 122-127).— C ylinders of nickel, p la tin u m , a n d g ra p h ite w ith a sm ali a x ia l hole d rilled in th em w ere th re a d e d on s to u t nickel o r p la tin u m w ires to give a v e ry loose fit, a n d th e angle a t w hich slip occurred w as d eterm in ed in m eno a n d in vario u s gas atm ospheres a fte r previous annealing in vacuo to rem oyo a ll tra c ę of surface films. Tho resu lts show th a t in vacuo a n d in a n in e rt gas atm o sp h ere (nitrogon o r argon) severe stick in g of th e m etals to one a n o th e r occurs, so t h a t no slip ta k e s place even w hen th e w ire is v ertical unless it is s h a k e n ; th is is a ttrib u te d to a k in d of cold-w elding by sim ple pressure a n d occurs on ly w ith perfectly clean surfaces. I n hydrogen, steam , a ir, o r th e v a p o u r of hy d ro carb o n s slip occurs w hen th e w ire is inolined a t 15°-62° to th e h o rizo n tal according to th e m etals in c o n ta c t a n d th e a tm o sp h e re ; th is effect is a ttrib u te d to th e fo rm atio n o f invisible films on th e m etal surface w hich allow slip to occur. T he presence of sueh films accounts fo r th e co n ta c t resistance in electric sw itchgear, &c.
—A . R . P .
1 9 3 6
I . — Properties o f M etals 243
*Experim ents on Two T hin M etal Film s Pressed Together. A Ioxander D eubner (N alurw iss., 1935, 23, 557).— T he n o n -lin ear rolationship betw een th e physical p ro p ertie s a n d th e th ick n ess of th e m e ta l films c a n n o t be exp lain ed by th e fa e t t h a t tho re a l film th ick n ess is n o t id en tical w ith th e th eo retical valuo derived from th e w eight of tho d eposited m etal, b u t th e p h cnom enon is a n a ctu a l p ro p e rty of th in m etal films.— B . BI.
*Diffusibility of D euterium in M etals. T . F ra n z in i (Nuovo cimcnlo, 1936,13, (2), 7 4 -7 8 ; S ci. A bs., 1936, [A], 39, 580).— E x p erim en ts w ere m ade to doter- mino w h eth er d eu teriu m difTuses th ro u g h m etals, p allad iu m being used as it is known t h a t h ydrogen is occluded by th is m etal. T ho prescnco of hydrogen an d d e u teriu m w as d eterm in ed spcctroseopically. T ho w ork show ed t h a t occluded hydrogen is rem oyed by a n electric field, b u t no evidenco for th is w as obtained in tlie caso of d eu teriu m .— S. G.
Adsorption Isotherm s. Critical Conditions. R . H . F ow ler (Proc. Cambridge.
Pb.il. Soc., 1936, 32, (1), 144-151).—S. G.
Sixth R eport o£ th e Comm ittee on Atomie W eights o£ the In te rn a tio n a l Union of Chemistry. G. P . B ax to r, O. H onigschm id, a n d P . L cbeau (./. A m er.
Chem. Soc., 1936, 58, (4), 541-548).— Sec M et. A bs., th is v o l„ p. 144.— S. G.
♦fThe M easurem ent o£ Contact P o ten tial Difference. C. W . O atley (Proc.
Roy. Soc., 1936, [A], 155, (885), 218-234).—M ethods of m casu rin g c o n ta c t p o ten tial differenees liith e rto used are c ritic a lly rcview ed a n d a new m eth o d is described, d ep en d en t on th e know n re la tio n betw een anodo Yoltage a n d critical m agnetie field in a m ag n etro n , w hen electrons from th e filam ent ju s t fail to reach th e anodo. R esu lts re la tin g to th e c o n ta c t p o te n tia l differenees of m olybdenum , zinc, a n d p la tin u m re la tiv e to a h o t tu n g ste n filam ent are briefly discussed.— J . S. G. T.
*Influence of E lectron Reflection on Photoelectric Em ission. W . B. N o ttin g ham (Phys. R ev., 1936, [ii], 49, (8), 646).— A b stra c t of a p a p e r rc a d beforo th e Am erican P h y sical Society. E lectro n s e m itte d th erm io n ically from tu n g s te n an d th o ria te d tu n g s te n filam ents a re d is trib u te d in energy as tlio u g h th e y suffered a reflection a t th e b a rrie r given b y R (p x) — c x p (— p x2l2mv>), w here co = 3-05 X 10-13 erg a n d px — m o m entum in oxcess of t h a t req u ired to go over th e b arrier. D u B ridge a n d o th e rs liavc show n t h a t Fow ler’s photoelectric theory w hich assum es reflection c o n sta n t (or zero) fits tlie ex p erim en tal d a ta . T his reflection m ay be in co rp o rated in to th e th e o ry . T h e new fu n c tio n is nearly id en tical in form w ith tho F ow ler cu rv e ov er th e ex p erim en tal rangę.
If th e reflection hy p o th esis be assum ed to be co rrect, a ll previous d eterm in a- tions of photoelectric w ork-functions aro too high b y a n a m o u n t given ap p ro x i- m atcly by = 8 + 0-1382' — 5 X 10"ST - m v. W hereas th o F ow ler a n a lysis gives w ork-functions fo r clean surfaces p ra c tic a lly in d e p e n d e n t of te m peraturo, th e new m e th o d w hen ap p lied to D u B ridge’s d a ta o n p allad iu m yiolds a negatwe te m p e ra tu ro coeff. of th e w o rk -fu n ctio n o f (4-5 ± 1) X 10"5 v.
p er degree. T h is is co n sisto n t w ith a tlierm ionic c o n sta n t A of 60 a m p ./
cm .3/degrce2, if i t be assum ed t h a t only 4 0 % of tho a p p a re n t surfaco em its, as is th o u g h t to be th e case fo r puro tu n g ste n , a n d includes th e effect of reflection.
— S. G.
On the Theory of th e Photoelectrom otive Force in Semi-Conductors. L . L andau a n d E . L ifsh itz (P hysikąl. Z . Sow jetunion, 1936, 9, (5), 477-503).—
[In English.] T h e e.m .f. t h a t a p p ears in a circ u it co n tain in g a som i-conductor illum inated from ono side is calcu lated . Two cases are considered : a sem i- conductor w ith eond u ctin g electrons a n d a scm i-conductor w ith cond u ctin g electrons a n d “ holes.” — S. G.
* Action o£ Periodically V arying Light on a M etallic P late. Q. M ajorana (A tti R . Acad. L in cei (Rom a), 1933, 17, 2 5 5 -2 5 6 ; Sci. A b s., 1933, [A], 36, 795).—
Deals w ith th e actio n of in te rru p te d lig h t on a lam p-blackened disc, w hich m ay be p a rtly due to h e a t, a n d describes a now m eth o d fo r com pensating th e photoelectric action. (See also follow ing a b stra e ts.)—S. G.
244 M etallurgical Abstracts
Vo l. 3*A ction o£ Light on T hin Metallic Lam in® . Q. M ajorana (Nvovo cimento, 1933, 10, (4), 2 6 1 -2 8 5 ; Sci. A bs., 1934, [A], 37, 212).— C ontinuing previous w o rk (see preeeding a b stra c t) i t is fo u n d t h a t th e electrical resistance of a th in lam in a of p la tin u m , silver, gold, a n d tin is increased w hen th e lam in a is stro n g ly illu m in ated . Tho effcct is v e ry sm ali w ith alum inium a n d zinc a n d is non- e x is tc n t w ith sodium . Besides y ary in g w ith th e n a tu ro of th e m e ta l, th e n m gnitude of th e effcct depcnds on tho thickness of th e lam in a a n d th o fre- quency of in te rru p tio n of th e lig h t. I f th e la m in a is im m ersed in ru n n in g w a te r th e effect is u n a ltc re d , b u t in still w a te r i t is sensibly reduced. T h ere is alw ays a phase lag in th e effect of a b o u t 45“ w hen p u lsatin g lig h t is u s e d ; in som e circum stances th is m a y be rcd u ced to a b o u t 35°. T h e expcrim cnts seem to show tlie existence of a new ty p e of d ire c t actio n of lig h t on elec trical re s ist
ance. U nlike th o photoelectric cffect, i t is n o t m anifested im m ed iately tho lig h t is in cid en t, n o r can i t be oxplaincd aw ay m erely on p u re ly th e rm a l grounds.— S. G.
*Photo-Resistance of M etals. Q. M ajo ran a (N vovo cim m lo , 1935, 12, (7), 409—417 ; Sci. A bs., 1936, [A], 39, 78).—A n acco u n t is given of fu r th c r investi- g atio n s of th e m etallic photo-resistance found b y M. (sce preeeding a b stra c t).
A fte r reference to fa c ts w hich d istin g u ish i t from a p u rely th e rm a l actio n of lig h t on th e resistanco of m etals, new determ in atio n s of th e phase lag <f> betw een p u lsatin g lig h t aetin g on th e m etallic lam in a a n d th e resistance of th e la tte r are described. I t is found t h a t fo r m etallic laminoe fixcd on glass <j> am o u n ts to a b o u t 45°, b u t m ay in exceptional cascs be as Iow as 16°; w h ils t fo r lam ina;
freo in a ir i t m ay be very noarly 90°, b u t som etim es only 65°. M oreover, <j>
inereases on decrease of th e frequency of th e lig h t, an d th is y a ria tio n is stro n g e st fo r lig h t from a m ercu ry lam p. T he re su lts confirm th e supposition of tho existence of a new p h o to electric effect th a t , in c o n tra st w ith th e o rd in ary p h o to electric effect, is in its n a tu rę r a th e r slow in its m anifestation.— S. G.
*Electric E quilibrium and P erm an en t Therm oelectric Currents in a Metallic Conduetor. F . Odono (N uovocim ento, 1935,12, (8), 522-530 ; S ci. A b s., 1936, [A], 39, 207).—T he th erm o d y n am ic th e o ry of phenom ena re la tin g to electric equilibrium an d th e passage of p e rm a n e n t c u rren ts in a m etallic co n d u eto r is considered. U sing th o id ea of a n electrochem ical p o te n tia l, a p a ra m e te r in tro d u c e d b y D uhem to ex p lain th e a ctio n betw een electric chargcs a n d m a te ria ł m asses, is show n th e existence of a p o te n tia l difference betw een th e in te rio r a n d th e surface of a m etal, of a n in te m a l a n d c x te m a l V o lta effcct.
Tho e.m .f. of a th erm o electric c u rre n t a n d th e coeffs. of th e P e ltie r an d T hom son effects in te rm s of th e e.m .f. of th e therm ocouple are calculated. I t is found t h a t th e w ell-known th e o ry due to K elyin is based on c o n trad icto ry hypotheses an d c a n n o t be accepted.— S. G.
* P erm an en t Therm oelectric Currents in M etallic Conductors. F . Odono (Nuovo cimento, 1936, 13, (1), 1 1 -1 5 ; Sci. A bs., 1936, [A], 39, 567).— Con
tin u in g preyious w o rk (preeeding a b stra c t) i t is shown t h a t th e th erm al phenom ena t h a t aro p roduced in a m etallic c irc u it in w hich a p e rm a n e n t c u rre n t is fiowing do n o t m odify th e free energy in th e conductor, b u t causo in s te a d a m odification of th e energy in tho su rroundings, w ith w hich th e co n d u cto r itse lf exchanges energy.—-S. G.
* F u rth er E xperim ents on Metallic Conduction. E r n s t W eb er (P hys. R ev., 1936, [ii], 49, (8), 643).— A b stra c t of a p a p e r re a d before th o A m erican P h y sical Society. Tho expcrim ents previously described (P hys. Rev„ 1933, [ii], 44 ,3 1 8 ; a n d M et. A bs., 1934, 1, 560) h av e b een co ntinued. T he d is trib u tio n of large d.c. in a fia t copper co n d u cto r in a stro n g m agnetic field p erp en d icu lar to th e flow of c u rre n t was in v estig ated , a n d its re la tio n so u g h t w ith th e ex p erim en ts of K a p itz a on th o increase of resistance in a m agnetic field (Note : N o d e ta ils are given in th e ab stra c t).— S. G.
1 9 3 6
I .— Properties o f M etals 245
Incandescence Electron Em ission and Electron Conduction in the Case o£
Solids. A. G ohrts (Z. tech. P h ysik, 1935, 10, (11), 370-373).— See M et. A bs., th is vol., p. 34.— S. G.
*Does M etallic Conduction O ccur in H ighly Compressed Metallic V apours?
W ern er B ra u n b e k (Z. tech. P h ysik, 1935, 16, (11), 497-498).— Sco M et. A bs., th is vol., p . 34.— J . S. G. T.
The Change of th e E lectrical R esistance an d of th e Reflecting Pow er of Metallic M irrors Condensed a t Low T em peratures. R . S u h rm an n an d G. B a rth (Z. tech. P h ysik, 1935,16, (11), 447-451).— Seo M et. A b s., th is v o l.,p . 34.— S. G.
*The [Electrical] R esistance of Very T hin Layers of Im purities in Metallic Contacts. R . H olm an d B . K irsch stcin (Z. tech. P h y sik , 1935, 16, (11), 4 8 8 - 494).—Sco M et. A bs., th is v o l„ p. 34.— J . S. G. T.
ReIaxation P henom ena in the T ransition from th e Supereonductive into the Non-Superconductive State. W . H . K cesom a n d P . H . v a n L a e r (Physica, 1936, 3, (3), 173-181; a n d K . Onncs Lab. Leiden Comrn. N o. 240c).—[In English.] Tho tra n sitio n from th e su perconductive to th e non-supcrconductive s ta te tak es place, as revealed b y ex p erim en ts on tin , w ith a re la x a tio n of several seconds, if i t is caused b y a n inerease of te m p e ra tu re of th e su b stan ce, -while a co n stan t m agnetic field is applied. N o such re la x a tio n (a t le a s t n o t to a n am o u n t of seconds) occurs if th o tra n sitio n is th o conscąuence of a n incrcaso of tho e x te m a l m agnetic field. These ex p erim cn tal faets aro in h arm ony w ith the views th a t , th e throshold value eurve being reached, th e re is a w eak coup] ing betw een th o ato m ie la ttic e a n d th e system of su perconduetive electrons, a n d th a t th ero is a stro n g eoupling betw een th e e x te rn a l m agnetic field a n d tho system of superconductive electrons as w ell as betw een th e non-superconduetive electrons an d th e ato m ie la ttic e .— S. G.
*An E xperim ental E xam ination of the E lectrostatic B ehaviour of Super- conductors. II . L ondon (Proc. B oy. Soc., 1936, [A], 155, (884), 102-110).—
l t is show n experim ontally t h a t th o lines of oloctrio in d u c tio n in a super- conductor te rm in a te disco n tin u o u sly in su rface charges a n d do n o t p e n e tra te a th in lay er of th e su p ereo n d u cto r.— J . S. G. T.
Electron Configuration in th e Superconducting M etals. U . D elilinger (Z.
tech. P h ysik, 1935,16, (11), 49S—i99).——See M et. /liis., th is vol., p . 35.— J . T.
flnyestigations in Strong M agnetic Fields. O. v. A uw ers (N aturw iss., 1936, 24, (5), 65-73).— R eview s re c e n t w o rk of K a p itz a on th e m agnetic beliayiour of nickel, m anganese, b ism u th , gallium , tin , bcry lliu m , m agnesium , a n d tungsten in stro n g m agnetic fiolds.— B . BI.
*An E lem entary Theory of the Change of R esistance in a Longitudinal Magnetic Field. A. Som m erfcld a n d B . W . B a r tle tt (Z. tech. P h y sik , 1935, 16, (11), 500).— See M et. A b s., th is vol., p . 35.-—J . S. G. T .
E stim ation of the M axim um T em perature in th e N eighbourhood of a Cross- Sectional Constriction of an Incandescent W ire in a n In e rt Gas. L eopold P rasnik (Z. P h ysik, 1936, 99, (9/10), 710-713).— T h e an aly sis alread y given for a n incandescent w ire in vacuo (Z. P h y sik , 1933, 86, 253) is h erc ex ten d c d to th e case of a n in can d escen t w ire h av in g a cross-scctional co n strictio n a n d h e a te d in a n in e rt gas. T h e re su lts are com pared w ith d a ta dcriv ed fro m tho filam ents of gas-filled lam ps.— J . S. G. T.
*Theory of Metallic Linking.—I . P a u l G om bas (Z. P h y sik , 1936, 99, (II/1 2 ), 729-742).—A m a th e m a tic a l th e o ry of in te ra to m ic forccs in m etals, em ploying H artreo ’s oigen-functions, is developed a n d ap p lied to dorivo v alu es of th e physical c o n sta n ts of th e p o tassiu m ato m . Tho follow ing values of th e respectiYo co n stan ts are d e r iy e d ; fo r com parison th o ex p erim en tal yalues are given in b rack ets : la ttic e c o n sta n t, 5-37 A. (5T 5 A .); la ttic e energy, 111-1 k.cal./m ol. (126-2 k .c a l./m o l.); h e a t of su b lim atio n , 11-4 k .cal./m o l. (26-5 k .c a l./m o l.); com pressibility, 2-6 X 10~n cm .2/d y n e (2-0 X 10-11 cm .s/dyne).
—J . S. G. T.
246 M etallurgical A bstracts
Vol. 3II.—PROPERTIES OF ALLOYS
(C o n tin u ed fro m p p . 198-202.)
S truetural A lum inium and Fatigue. F . H iF ra n k la n d . H e n ry D . Jo h n so n . R . L . T em plin (Eng. News-Record, 1936, 116, (20), 709-710).— Cf. M et. A bs., th is vol., p. 133. I n a le tte r, F . suggests t h a t a lu m in iu m alloys are p a rtic u la rly susceptible to red u etio n of fa tig u e-stren g th b y n o tch effects, a n d d ire e ts a tte n - tio n to th e ir Iow enduranco lim it. R eplies b y J . a n d T . include d a ta on th e fatig u e lim its of “ 27 S T ” alloy a t 10 X 108 eycles (19,000 lb ./in .2) a n d 500 X 10° eycles (13,000 lb ./in .2). A ttc n tio n is d irected to th e a d v an ta g es of th is alloy’s Iow m odulus of e lasticity a n d to th o valuo of precise know lcdgo of th e p ro p erties of m aterials in engineoring design.— J . C. C.
The E ndurance Lim it of A lum inium Alloys. R . Irm a n n (Congr&s internat.
M in es M it. Geol., Section de M ćtallurgie, 1 9 3 5 ,1 ,4 3 5 —140 ; a n d R ev. M U ., 1936, 33, (4), 231-236).— [I n F rencli.] Seo M et. A b s., th is vol., p. 113.— S. G.
*M agnetic Investigation of P recipitation-H ardening [o£ A lum inium -C opper Alloys]. H erm an n A uor (Z. tech. P h y sik , 1935, 16, (11), 486-488).—Seo M et.
A bs., th is vol., p, 36.—J . S. G. T .
flm p ro y em en t of A lum inium Alloys. M. I . Z ah aro v a (M etallurg (M etal
lurgist), 1936, (2), 92-101).— [In R ussian.] A su rv ey of th e ageing o f alu- m in iu m -co p p er alloys, alum inium -m agnesium -silicon alloys, D u ralu m in , a n d alum inium -silieon alloys, a n d o f th e influenco o f p lastic d efo rm atio n on th e disin teg ratio n o f solid solutions.—N . A.
*A Ium inium -M agnesium Alloys. P ie rre V a c h e t (Congrls internat. M in e s M et. Geol., Section de Mćtallurgie, 1935, 1, 175-1 8 7 ; also (in E nglish) L ig h t M etals Research, 1936, 4, (23), 4 1 1 -4 1 4 ; a n d A lu m in iu m and N on-F crrous R ev., 1936,1, (7), 301-309).— [I n F rencli.] Seo M et. A bs., th is vol„ p . 73 — S. G.
A Q uatem ary A lum inium -Silicon Alloy. D evelopm ent an d Properties of Cetal. G. W olter (M et. In d . (Lond..), 1936, 48, (23), 627-634).— A n acc o u n t of th e p ro p ertie s of a n alloy consisting essen tially of copper 3, zinc 10, Silicon 6-5% , alum inium rem ain d er. Com parisons are m ado w ith tho u su a l s ta n d a rd alloys (seo J . In st. M etals, 1926, 36, 325).— J . E . N .
tB eryllium . R o b e rt G adeau (Ćonsjres internat. M in e s M et. Geol., Section de M ćtallurgie, 1935, 1, 1 8 9-199; a n d A lu m in iu m and N on-F errous R ev., 1936, 1, (8), 353-360.)— [In F rench.] Seo M et. A b s., th is vol„ p . 74.— S. G.
*The E lectrical R esistance o£ B ism uth AUoys. N . T hom pson (Proc. Roy.
Soc., 1936, [A], 155, (884), 111-123).—T h e elec trical resistan ces of single cry stals of b ism u th co ntaining sm ali p ro p o rtio n s of lead , tin , germ anium , sclenium , a n d tellu riu m w ere d eterm in ed a t 14°-400° K . L ead , tin , a n d g er
m anium dissolvo in th e b ism u th la ttic e a n d pro d u ce a n alloy liaving a largo negativc tem p eratu ro coeff. of resistance p arallel to th o p rin c ip a l ax is of th e c ry s ta l. Tlie effect is sim ilar, b u t sm ali, p erp en d icu lar to th e axis. Selcnium a n d tellu riu m dissolve in b ism u th , reducing its speeific resistan ce b o th p arallel a n d p erp en d icu lar to th e ax is ex c e p t a t Iow te m p e ra tu re s. T h e y give no negativo te m p e ra tu re coeffieient. T lie re s u lts a rc ex p lain cd q u a lita tiv e ly in te rm s of Jo n e s’s th e o ry of b ism u th .— J . S. G. T.
*On the M agnetic B ehaviour of th e System C hrom ium -Sulphur. H a a k o n H arald sen a n d A nna N cuber (N aturw iss., 1936, 24, (18), 280).— S u scep tib ility m easurem ents in th e rango CrS-C r2S 3 show t h a t w ith in a sm ali co n cen tratio n rangę th e sy stem becomes m ark ed ly ferrom agnetic b u t a t 165° K . a n unex- pected sh arp decrease in th o m agnetism occurs such as is n o t fou n d in o th e r ferrom agnetic m aterials a t te m p e ra tu re s below th e Curie p o in t.— B. BI.
*On th e Lower Sulphides o£ Cobalt. The E quilibrium D iagram of th e System Cobalt-Cobalt Sulphide. O tto H u lsm an n an d F rie d ric h W eibke (Z. anorg.
Chetn., 1936, 227, (2), 113-123).—T herm al, m icrographic, a n d X -ra y exam ina-
1 9 3 6
I I .
—Properties o f A lloys 247
tion of th e sy stem cobalfc-cobalt su lp h id e show s t h a t th o so lu b ility of su lp h u r in c o b alt is alm o st zero a t room te m p e ra tu rę . Tho eu te c tic occurs a t 874° C.
an d 26-4% su lp h u r. Tho (5-phaso ( C o .^ ) has a hom ogeneous ran g ę of 1-3%
cobalt a n d is sta b le on ly above 787° C., below w hich i t decom poses in to th e cobalt-y eu tec to id . T h e y-phase, w hich h as a face-centred cubic s tru c tu re is form ed by a peritectic reactio n a t 928° C. a n d has th e com position Co0S5. T he 8-phase is hom ogeneous only a t th e com position CoSi.05.—A. R . P .
Deflnite Compounds in Alloys [C opper-A lum inium ]. E . A m ic (Rev.
Fonderie modernę, 1936, (Feb. 2), 71).— R . T hew s (ibid., 1935, (A pr. 25)), sta te d t h a t in p re p a rin g b in a ry m a s te r alloys of copper a n d alu m in iu m , an inerease in te m p e ra tu ro of 280°-330° C. occurs, “ w hich has n o t becn com pletely explained.’! A. s ta te s t h a t th is eso tlierm ic re a c tio n is due e n tire ly to tho successive fo rm atio n of tho in term etallic com pounds CuAl., a n d CuAl. [ I t has long been p ro v e d t h a t th o h e a t com cs from re d u c tio n of th e oxido in th e copper b y alum inium .— E d.]—J . E . N .
*The Effect of Iro n Im purities on the A nnealing of H igh Brass. (G ibson a n d Doss.) Sce p. 274.
*The R ecrystallization of Copper-Zinc Alloys w ith Z inc Contents up to 7 P er Cent. Al. K itaig o ro d sk i (Tech. P hysics U .S .S .R ., 1936, 3, (1), 3 9 -5 0 ; S ci.
Abs., 1936, [A], 39, 579).— [I n G erm an.] A lloys wero p re p a re d co ntaining up to 7% zinc b y m elting copper a n d zinc to g e th e r (o) in purified nitrogen, an d (6) u n d er cliarcoal in a ir, w ith su b sc ą u e n t deo x id atio n . R ecry stallizatio n was determ ined on a 97 -9 8 % cold-w orked s trip b y a n X -ra y m eth o d . A t a b o u t 2% zinc tho ra to is a m inim um as show n b o th b y tim e an d by tem p eratu ro curves. Tho speed is n o t affected by 0-2-0-4% phosphorus n o r b y cuprous oxide w hich m ark cd ly in h ib its recry stallizatio n in p u re copper. T he oxide is ap p arcn tly im m ed iately rcd u ced by zinc. T heoretically, recry stallizatio n depends on th e n u m b er of nuclci a n d ra tę of g ro w th , so t h a t i t is unnecessary to assumo th e fo rm atio n of a special c o n stitu e n t a t 2 % zinc. T h eo retical investigation of recry stallizatio n is v e ry difficult. T he p ra c tic a l rulo (ro- cry stallizatio n te m p e ra tu re /m e ltin g p oint) = co n st. h as no th e o re tic a l o r experim cntal basis fo r th o alloys in y estig ated .— S. G.
^Influence o£ Im purities on the P roperties of M agnesium Alloys. N . W . Agccw, M. I . Z am o to rin , a n d D . N . S h o y k et (M elallurg (M etallurgist), 1936, (3), 27-38 ; (4), 48-59).— [In R u ssian .] T ho influenco w as stu d ie d of Silicon (up to 2% ), iro n (up to 0-18% ), n itro g en (up to 1% ), sodium (up to 0-98% ), potassium (up to 0-72% ), calcium (up to 0-99% ), m agnesium oxido (up to 1 •()%), a n d chlorides (up to 0-51% Cl) on c a s t E le k tro n alloys co n tain in g alum inium 6-1 0 , m anganese 0-0 -1 8 , zinc 0 an d 2-98, a n d cop p er 0 a n d 1-04% , a n d on rolled alloys co n tain in g alu m in iu m 1-5-6, zinc 1-4-5, m anganese 0-0-2, a n d copper 0 -0 -7 5 % . Silicon causes stro n g a b so rp tio n of gases, inerease in p o ro sity , g re a te r te n d en c y to segregation, inereased co n tractio n , g reato r hard n ess a n d b rittlen ess, low er resistan ce to im p a c t, a n d sm aller clongation a n d re d u c tio n in arca, b u t th o change in m echanical p ro p ertie s w ith te m p e ra tu re is less th o higher th o % S i l i c o n , a n d th ere is a g re a te r ten d en c y to age-harden. Ir o n dissolves u p to 0-2% red u cin g th e c o n tra c tio n a n d in- creasing th e hard n ess an d tensilo s t r e n g th ; i t h as no olToct on ageing o r rolling.
N itrogen reduces co n tra c tio n , inereases p o ro sity , a n d low ers th o m echanical properties a t a ll te m p e ra tu re s. Sodium in ten sifiesliq u atio n , inereases p o ro sity , causes th e fo rm atio n of cracks in th e lią u a tio n zone, a n d seriously a n e c ts th e m echanical p ro p erties, th o p la stic ity d isap p earin g en tire ly w ith 0-9% sodium a t room te m p e ra tu re a n d w ith on ly 0-3% sodium a t 150°-300° C., w hile tho tensile s tre n g th , clongation, a n d re d u c tio n in a re a decrcaso a t hig h te m p e ra tures. E v en as little as 0-09% sodium p re v e n ts h o t ex tru sio n of E le k tro n . P otassium has a sim ilar effect to sodium , b u t does n o t im pede rolling. Calcium is a good deoxidizer fo r m agnesium a n d its alloys. C ast E le k tro n alloys even
248 M dallurgical A bsłra cts
Y o l. 3 w ith 0-3% calcium havo a clcan surface frco from oxide an d n itrid e s. Calcium inereases th o d en sity a n d , u p to 1% , does n o t affect th e m echanical properties, ageing, o r rolling. M agncsia reduces lią u a tio n a n d slirinkage a n d p rovcnts th e dovelopm ent of tran scry stallizatio n . W ith 0-1% m agncsia th o m echanical p ro p ertie s aro unaffected, b u t w ith 1% th e y a ll decrease.—N . A.*A ge-H ardening of M agnesium -A lum inium Alloys. A. M .T alb o t a n d J o h n T . N o r to n (M etals Technology, 1936,3, (2), 13 p p . ; A .I .M .M .E . Tech.P ubl. 692).—
Tho ago-hardoning of a in ag n esiu m -alu m in iu m alloy co n tain in g 9-6% a lu m in iu m w as stu d ie d b y m easurem ents of h ard n ess, d ilatio n , a n d elec trical resist- a n c o ; la ttic e p aram eto r m easurem ents were also m ade b y a back-reflection cam era on a fiat surface of a błock, tho sam e su rface being u sed su b seq u en tly fo r etch in g a n d m icroscopic cx am in atio n . A ll th e o b serv atio n s are accounted fo r by th e sim ple p re cip itatio n th eo ry , an d no cvidence fo r pro -p recip itatio n - hard en in g was o b tain ed . T he fa c t t h a t no appreciable chango in la ttic e p ara- m eter occurs u n til a fte r considerable increase in h ard n ess is duo to tho precip ita- tio n ta k in g płaco v ery unev en ly , so t h a t fcho nrnin b u lk of tho allo y m ay bo unchangod w h ils t sm ali arcas show com plete p re c ip ita tio n . U n d er such con
d itio n s X -ra y diffraction p ic tu re s m a y show only lines duo to th o unchangod solid solution, b u t b y careful co n tro l tw o sots of lines m ay bo o b tain ed , one corrcsponding to tho p rc c ip ita tc d a n d th e o th e r to th e unchangod areas.
— W . H .-R .
♦Stress-Relief A nnealing H igh-Strength M onel M etal P latę. (K osting.) Seo p. 274.
The Change of M agnetization of Nickel, Perm alloy, and Nickel Single Crystals in Strong Fields. (Gerloff.) Seo p. 239.
*Magnetic Pow der E xperim ents on Rolled N ickel-Iron. J . L. Snoek (P hysica, 1936, 3, (2), 118-124; S ci. A bs., 1936, [A], 39, 429).— [I n E nglish.] Tho m agnetie pow der p a tte m s o b tain ed b y B itte r (M et. A bs. (J. In s t. M etals), 1933, 53, 8) on tho surface of n io lten u n stra in e d forrom agnetie bodies aro briefly described an d th e ir origin discussed. I t is suggested t h a t two phenom ena aro presen t— ono du e to inhom ogcncities in th o m a te ria ł a n d th e o th e r to tho m agnetie S tate of th e m a te ria ł a n d tho m agnetization process. T ho la t te r is in v estig ated b y stu d y in g tho pow der figures a n d th e m agnetization euryes of a 5 0 % n ick el-iro n alloy in tho annealed sta to (“ isotropic ” specim en) a n d in tho un an n ealed condition (“ anisotropic ” specim en). M arked diflerences aro observed betw een th e tw o. T h e generał properties of th e B itte r p a tte rn s aro d e sc rib e d ; tho m o st im p o rta n t of these is t h a t th o lines are p arallel to th e d irectio n of oasiest m agnetization.— S. G.
*A pparatus for the D eterm ination of L ength V ariations of In v a r W ires 24 m . Long. P . W erkm eister (Z. Instrum enlenkim de, 1935, 55, (12), 4 9 9 -5 0 1 ; S ci.
A b s., 1936, [A], 39,102).—D escribes a m ethod for d eterm ining th e y ariatio n s in len g th of 25 m . I n v a r w ires. T hree w ires are in d iv id u ally com pared w ith 24 m.
bases se t u p on a su itab le w ali of a 3-storey building, one base being arran g ed on each floor. T he average accu racy of com parison is betw een ± 0-02 a n d
± 0-03 m m ., and it is established t h a t in tho case of th e 3 wires used no changes g re a te r th a n 0-1 m m . ta k e place w ith in 5 years. T h is is confirm ed b y sta n d a rd i- zatio n of th e w ires a t th e Physikalisch-T ochnische R eich san stalt.— S. G.
♦Photoelectrie Sensitiyity of P alladium -Silver Alloys S aturated w ith Hydrogen.
F . K ru g e r a n d W . K allenbach (Z. Physilc, 1936, 99, (11/12), 743-750).—
P a lla d iu m -silv e r alloy3, s a tu ra te d w ith hydrogen, show a p rin cip al m ax im u m photoeleotric se n sitiv ity in th e caso of alloys co n tain in g 2 0 % of sily er a n d a low er m axim um fo r alloys co ntaining 6 0 -6 5 % of silyer. T hese com positions correspond v ery olosely w ith th e com position of th e alloys absorbing a p rin cip al a n d secondary m axim um p ro p o rtio n of h y drogen. Theso resu lts aro discussed in connection w ith th e resu lts o b tain ed by S chniederm ann.—J . S. G. T.
1 9 3 6
I I . — Properties of A lloys 249
*Binary Systems o£ A lkali M etals.—I [R ubidium -P otassium ; R u b id iu m - Sodium]. Carlo G oria (Gazz. chim . ilal., 1935, 65, 865-870 ; G. A b s., 1936, 30, 3305).— T he sy stem s ru b id iu m -p o ta s siu m a n d ru b id iu in -so d iu m w ere stu d ie d . The th e rm a l d iag ram of th e sy stem ru b id iu m -p o ta s siu m in d icates a lim ite d rangę of solid solutions, th o absencc of a n y com pounds, b u t th o fo rm atio n of a eutectic a t 34° C. w ith 15% of p o tassiu m . T he ru b id iu m -so d iu m d iag ram indicates tho absence of solid solutions a n d of com pounds, b u t show s a eu tectic a t — 5-2° C. w ith 92-0% ru b id iu m . T he re su lts confirm th o se of R in c k (M et.
Abs. (J. In s t. M etals), 1933, 53, 4 9 5 ; M et. A b s., 1934, 1, 7 5 ; 1935, 2, 283).
The tech n iq u e of p re p a ra tio n of th e alloys is described.—S. G.
tT h e M echanical Properties of Tin-B ase Alloys. D . J . M acn au g h tan a n d B. P . H aig h (Gongr&s internat. M in es M U . Giol., Section de M U allurgie, 1935, 1, 2 3 5-241; an d ltev. M et., 1936, 33, (1), 7-13).— [In F re n c h .] See M et. A b s., th is vol., p . 38.— S. G.
*The Effect of the A ddition of Lead on the E ndurance Lim it of a Certain T in- Base B earing Alloy. J o h n N . K cn y o n (A m er. Soc. Test. M a t. 1’reprint, 1936, 4 p p . ; a n d M et. In d . (Lond.), 1936, 49, (2), 33-34).— C o n tin u atio n of an iiw estigation com m enced sev eral y ears ago to d eterm in e th o e lle c t of tlie ad d itio n of lead to c e rta in tin -a n tim o n y -c o p p e r B a b b itt m e ta ls (M et. Abs.
(iJ . In st. M etals), 1933, 53, 495). T ho a d d itio n of 4 % of lead has little effect on tho endurance p ro p ertie s of a tin -b ase b earing alloy (tin 80, an tim o n y 15, copper 5 % ) ; if lead h as an y e lle c t a t a ll i t is to im provc th e m a te ria ł. A pcculiar form of bearing failu re w as fo u n d to occur a fte r th e alloy has been in serviee fo r a long tim e a n d an e x p lan a tio n of th is failu re is oflered.— S. G.
*SpectraI Em issivities, Resistivity, and T herm al Expansion of T u n g sten - Molybdenum Alloys. P . N . B o ssa rt (Physics, 1936, 7, (2), 50-5 4 ).—Tho sp ectral em issivities of 3 d ifferen t tu n g ste n -m o ly b d e n u m alloys w ere d eter- m in ed ; tho em issivitics of tu n g ste n an d m olybdenum w ere also m easu red . The re s istiv ity -te m p e ra tu rc a n d th e rm a l e x p a n sio n -te m p e ra tu rc re la tio n s a re given fo r tho alloy co n tain in g 46-5 ato m s-% tu n g ste n . Tho re s istiv ity re la tio n is com pared w ith those of its c o n stitu e n ts a n d discussed w ith reference to tho th eo ry of B ragg a n d W illiams.-—S. G.
*Investigations on th e W ear of M etals in Sliding Friction. B runo K e h l an d E rich Sicbel (Arch. Eisenhuttenwesen, 1935-1936, 9, (11), 563-570).—T h e w ear, friction, an d ten d en c y to seize of c a st bronze, lead ed bronze, a n d w b ite m etal bcarings in c o n ta c t w ith steel sh a fts w as d cterm in ed , using p u re oil an d o il- cm ery in ix tu res as lu b ric a n ts. U n d e r oil th e te n d en c y to seize inereases w ith inereasing surface roughness a n d in p u re oil th e w ear deereases w ith inereasing tim e of te s t ow ing to tho g ra d u a l increase in sm oothness w hioh occurs. W ith co n sta n t lo ad tho speed of ro ta tio n has no influence on th e w ear in o il-cm ery m ixtures, b u t w ith inereasing load th e w ear inereases a t first p ro p o rtio n al to th e load a n d th e n as seizure occurs to several h u n d re d tim es th o n o rm al yalu c.
L cadcd bronze h ad th e sm allest coeff. of frictio n of th e alloys te ste d .— A. R . P .
*Irreversible T ransform ations in Solid Solutions. J . B. F rid m a n (Z h u m a l Tehnicheskoy F izik i (J . Tech. P hysics), 1936, 6, (1), 78-82).— [ I n R u ssian .]
In b in ary n ie k e l- an d m an g an e se-iro n alloys th e h ysteresis of tlie a -y - tra n s - form ation is a lin ear fu n ctio n of tho eo n cen tratio n , th e elTects of tlie niekel an d m anganese being p ro p o rtio n al to th e ir ato m ie ra d ii. I n te rn a ry n ic k e l- ch rom ium -iron alloys, a n d in th e se p aratio n a n d redissolution of carbides in nickel-chrom ium steel, hysteresis inereases a p p ro x im a te ly d ire e tly w ith tho concentration. T h e com bincd effect of te m p e ra tu re a n d d eform ation in nickel-iron an d n ick el-ch ro m iu m -iro n alloys is to reducc th o h ysteresis by 17-25% .—N . A.
Ecjuation of State an d H eat of P hase Transform ations in Solids. Y . A.
T ro tzk iy (Z h u m a l Tehnichcskoy F iz ik i (J. Tech. P hysics), 1936, 6, (1), 125- 136).— [In R ussian.] F ro m tho c q u atio n o f sta to o f a solid, a n d ta k in g in to
250 M etallurgical A bstracts
Yo l. 3a cco u n t its crystallino stru c tu re , its h e a t o f tran sfo rm atio n (<2) is given b y tho expression: Q — 9i?312(«2a 3 — n ya lt w here T is tho te m p e ra tu re a n d a Ł a n d oc2 are tho coeff. o f expansion a n d a n d n 2 co n stan ts characterizin g tho cry sta l la ttic e before a n d a fte r tran sfo rm atio n .— N . A.
*R epresentation o£ T ernary Systems. E ric h Scheil (Arch. Eisenhiillenwesen, 1935-1936, 9, (11), 571-573).—To fa c ilita te th e re a d in g of te rn a ry d iag ram s i t is suggested t h a t th e y should bo accom panicd b y p lan s show ing tho. 3- a n d 4- p hase eą u ilib ria in th e system an d th o ir re la tio n s to one a n o th e r. E x am p les of th e follow ing systcm s are given inter alia : ir o n -e o b a lt-tu n g s te n , ir o n - F e 3C - eopper, iro n -ch ro m h im -carb o n , iro n -m a n g a n e se -e a rb o n , a n d iro n -z irc o n iu m - c arbon.—A. R . P .
III.—STRUCTURE
(M etallo g rap h y ; M a cro g rap h y ; C ry stal S tru c tu re .)
(C o n tio u ed fro m p p . 202-203.)
*On Grain-Size in M etals. M. G. O knov (M elallurg (M etallurgisl), 1936, (3), 3-8).— [In R ussian.] F ro m experim ents on th e effects o f u p to 1% o f n u m e r
ous m etals on th e cry stallizatio n o f p u re zinc, th e red u ctio n in grain-size caused b y c ertain im purities is a ttrib u te d to tlie fo rm atio n o f a disperse oxide phase (e.g. m agnesia, alum ina, o r linie) w hich prom otes th o fo rm atio n o f num erous cry stallizatio n nuclci b u t th is th eo ry alone is insuffieient to oxplain a ll cases o f grain-size red u ctio n ; th u s w hen m ercury is ad d ed , th e w ide tem p eratu ro in te rv a l w ith in w hich sep aratio n o f exeess zinc ta k e s place m a y be considered as one o f th e factors.—N . A.
♦Grain Changes in a-C opper Solid Solutions in the Cast Condition Produced by A nnealing. M. P . S lavinskiy, O. S. M alhasjan, a n d L. R . E d elso n (M etal- lurg (M etallurgisl), 1936, (3), 8-15).— [I n R u ssian .] T ests o n b rass w ith 30, 37, an d 4 0 % zinc, a n d on p h o sp h o r-b ro n ze w ith (a) t i n 4-5, phospliorus 0-02%
a n d (6) ti n 6, phospliorus 0-2% show ed t h a t a-solid solutions of copper can be recry stallizcd in th e c a s t s ta tc p ro v id ed t h a t tlie annealing is prolonged to overcom e th e effects of segregation. A lloys n e a r th e lim it of th e solid so lution ran g ę recrystallize m ore ra p id ly due to volum e changcs in th e segre- g a te d regions betw een tho g rains. B rass show s a g re a te r grain -g ro w th th a n
bronze.—N . A.
♦Dependence o£ Diffusion Veloeity in Metals on Crystallographic O rientation (Anisotropic Diffusion). W . B ugakow a n d N . B reschnew a (Tech. P hysics U .S .S .R ., 1935, 2, (5), 4 3 5 -4 4 3 ; S ci. A is ., 1936, [A], 39, 225).— [In G erm an.]
A n in v estig atio n w as m ade of th e velocities of diffusion of m ercu ry in to cadm ium a n d in to zinc single cry stals in different cry stallo g rap h ic direetions.
I n b o th cases th e diffusion velocity is g re a te st in th e d irection parallel to th e base p ian e a n d le a st p erp en d icu lar to th is pian e. Increase of te m p e ra tu ro decreases th e im portancc of tho cry stallo g rap h ic d irectio n fo r th e velocity of th e process, i.e. i t decreases th e degree of an iso tro p y of tho diffusion. T he diffusion veloeity of copper in to zinc u n it c ry sta ls w as also iiw c stig a te d a n d analogous resu lts o b tain ed .— S. G.
♦Diffusion Coefficients of Metals and G rain M agnitudes. W . B ugakow a n d F . R ybalko (Tech. P hysics U .S .S .R ., 1935, 2, (6), 617-6 2 3 ; S ci. A bs., 1936, [A], 39, 225).— [I n G erm an.] T h is in v estig atio n deals w ith th e a lte ra tio n in th e diffusion coeffs. of b rass on tra n sitio n from single- to poly-crystals a n d fo r d ifferen t g rain m ag n itu d es in th e poly-crystal. T h e absolute v alu e of tho diffusion coeff. increases appreciably d u rin g th e tra n sfo rm a tio n from single- to p oly-crystals. T h e h e a t of relax atio n , w hich has been e v a lu a te d from th e te m p e ra tu re curve of th e diffusion coeff., decreases on tra n sitio n from th e single- to th e poly -cry stal, b u t rem ains c o n sta n t d u rin g fu rth e r d im in u tio n of
