METALLURGICAL A B S T 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 )
V o lu m e 2 J A N U A R Y 1 9 3 5 P a r t 1
I.— PROPERTIES OF METALS
•¡•Service Characteristics of the Light Metals and Their Alloys. (Amer.
Soc. Test. M at., 1934, pp. 33).—P repared b y Sub-Comm ittee V II of Com
m ittee B -7 on L ight M etals an d Alloys of th e A.S.T.M. in conjunction w ith th e American F oundrym en’s Association. The following subjects are dis
cussed : ( 1) metallurgical characteristics—compositions and forms available, applicability to fabricating processes (including m ethods of casting of cast alloys), types of h eat-treatm en t possible, w elding; (2) industrial requirem ents of th e aircraft, autom otive, general stru ctu ral, architectural, railw ay equip
m ent, and household appliance industries; (3) surface protection—painting, oxide coatings, electroplating. I n ta b u la r form are given : (1) tra d e desig
nations, (2) nom inal compositions, (3) typical mechanical properties of cast an d of w rought alloys of alum inium and of magnesium, (4) compositions of ingot alum inium, (5) physical constants of alum inium an d magnesium, (6)* physical properties of magnesium alloys, (7) foundry characteristics of alum inium and magnesium casting alloys, and (8) fabricating characteristics of w rought alum inium alloys. A bibliography is included. [A ote by Abstractor : I t is impossible to do more th a n indicate th e contents of this valuable up-to-date sum m ary of knowledge of light alloys in use in A m erica;
especially as th e booklet is itself in th e n a tu re of a n ab stra c t.]—R . B. D.
A Simple Means for Distinguishing the Various Qualities of Aluminium.
A. von Zeerleder (A lu m in iu m , 1934, 17, 88-90).—Two tests are made, one a scratch te s t w ith an Aldrey needle (Brinell hardness 70-80) and th e o th e r a chemical te s t in which a drop of 20% caustic soda solution is allowed to rem ain on the polished surface for 10 minutes. In th e scratch te s t pure alum inium and its alloys w ith sm all quantities of other metals, e.g. A lum an and Anticorodal, are m arked by th e needle, whereas th e harder alloys such as D uralum in are u n affected. The soda te s t reveals th e presence of copper in the alloys by th e pro
duction of a black spot. F or distinguishing^ hard-w orked from annealed alum inium, scratch tests m ay be m ade w ith h ard and w ith annealed Aldrey needles. Exam ples of th e use of th e tests are shown in photographs.—A. R . P .
|0 n the Effect of Increasing the Purity on the Properties and Working of Aluminium. H. Rohrig (A lum inium , 1934, 17, 7 9 -8 4 ; an d (translation) Light Metals Research, 1934, 3, 233-242).—R ecent w ork on th e properties of 5 grades of alum inium varying in p u rity from 99-39 to 99-995% is reviewed and th e results are tabulated. W ith increasing p u rity th e surface of castings becomes sm oother and brighter and th e crystal structure gradually becomes less complex u n til finally a purely large-grained polygonal stru ctu re is obtained when th e im purities are less th a n 0 -01% ; th e p urest m etal has a Brinell hardness of 13-9 w ith an electrical conductivity of 38-1 m ./ohm . m m .2.
The resistance to corrosion by a m ixture of nitric an d sulphuric acids decreases rapidly w ith increasing im purities w hen th e m etal is in th e hard-rolled state, b u t there is relatively little difference after annealing a t 500° C. and quenching.
A 2% copper alloy made w ith pure alum inium after quenching from 590° C.
shows a pure polygonal grain stru ctu re, b u t a sim ilar alloy m ade w ith alum in
ium containing 0 -2% iron a fte r th e same h e a t-tre a tm e n t shows num erous
* Denotes a paper describing the results of original research, f Denotes a first-class critical review.
2 M etallurgical Abstracts
Vo l. 2 irregularly d istrib u ted islets, a te rn a ry iron-copper-alum inium constituent, an d th e grain boundaries are very irregular.—A. R . P .♦Study of the Cooling of Metals [Aluminium] by Air. P . V ernotte an d E . Blouin (Aérotechnique (Suppt. to Aéronautique), 1934, 12, 25-26).—A brief, illu strated account of m ethods used to stu d y th e h e a t exchange betw een a block of alum inium an d currents of cold a ir passed a t various air speeds thro u g h a passage cu t down th e axis of th e block. Curves showing th e v ariation of th e coeff. of th erm al exchange w ith air speed are given for holes of circular an d trefoil sections.—J . C. C.
fThe Thermal Properties of Aluminium and Their Applications. A. de B iran (Light Metals Rev., 1934, 1, (3), 38-49).—T ranslated from Rev. A lu m inium , 1933, 10, 2263-2278; 1934, 11, 2311-2332. See M et. A bs., 1934, 1, 161, 225.—R . B. D.
The Light-Reflecting Properties of Aluminium and Its Alloys as Affected by Surface Treatment. H ase (A lum inium , 1934, 17, 20-25).—The regular and diffuse reflections of lig h t a t a n angle of incidence of 45° C. from surfaces of alum inium , P an tal, an d P o lital w hich have been tre a te d in various ways, e.g. highly polished, lacquered, E loxal-treated, pickled, and scratch- brushed, are shown graphically an d briefly discussed.—A. R . P .
*The Hall and Allied Effects in Cast Bismuth Plates as Affected by the Rate of Cooling. L. H ow ard P etersen (Proc. Ind ia n a Acad. Sci., 1933, 43, 185- 190).—The therm om agnetic an d galvano-m agnetic effects in bism uth plates are influenced b y th e ra te of solidification (structure) of th e allov. W hen th e m ould of liquid bism uth was cooled in a freezing m ixture a t —Î0° C., th e expansion on solidification was rap id enough to eject portions of m etal.—R . G.
*The Magnetic Moment of the Nucleus of Cæsium. D. A. Jackson (Proc.
Roy. Soc., 1934, [A], 147, 500-513).—The nuclear m agnetic m om ent of cæsium is found, from spectroscopic evidence, to be 2-75/1838 m agneton to w ithin 5 % .—J . S. G. T.
*The Exact Measurement of the Specific Heats of Metals at High Tempera
tures. XVII.— Calorimetrical Retardation Phenomena in the Case of Cerium and Chromium. E . M. Jaeg er an d E . R osenbohm (Proc. K . Alcad. Wet.
Amsterdam, 1934, 37, 489-497).— [In English.] Values of th e m ean specific h e a t of cerium betw een 290° an d 400° C. an d betw een 450° an d 550° C. are found to depend on th e prelim inary th erm al tre a tm e n t of th e m etal an d its subsequent cooling. I t is possible th a t a real tran sitio n tem p eratu re exists betw een 360 an d 370° C. This conclusion is confirmed by X -ra y analysis a t ordinary tem peratures. The phenom enon is associated w ith th e occur
rence of so-called one-phase tran sitio n s s’ as already show n to occur in beryllium an d zirconium . A sim ilar ty p e of tran sitio n is also show n by chrom ium an d revealed by m easurem ent of th e m ean specific h e a t of th e m etal w ithin various tem p eratu re ranges betw een 400° an d 1066° C. J . T.
* The Refining of Metals by Sublimation in a High Vacuum: Chromium Aluminium, Silicon, Beryllium. W. K roll (Metallwirtschaft, 1 9 34,13, 725-731,’
789). These m etals can be distilled in a high-frequency vacuum furnace.
Good separation from im purities can be obtained read ily w ith alum inium . Beryllium can readily be distilled free from all im purities o th er th a n alum inium an d magnesium , b u t even so th e p ro d u ct is alw ays b rittle .—v. G.
♦Effect of Cold-Rolling on the Indentation Hardness of Copper. J o h n G.
T ho-P scm (J. R es. N at. B ur. Stand., 1934, 13, 745-756 ; Research P aver No.
742). specim ens of tough-pitch electrolytic copper, com m ercial oxygen-free copper, an d single crystals of copper of different orientations were subjected to severe cold-rolling to determ ine th e effect on th e properties, p articu larly on th e hardness. In all cases th e in d en tatio n hardness increased to a m axim um value which was m aintained during subsequent reduction u n til th e hardness determ inations became unreliable owing to th e thinness of th e specimens.
1935
7 .— Properties o f Metals 3
No irregularities were encountered except in the case of very tln n specimens.
The results were confirmed by determ inations of tensile strength of some of the specimens «and by th e application of Meyer’s analysis to some of the d ata. 1 he effect of severe cold-rolling on th e indentation hardness of copper was not m aterially affected by th e initial hardness of th e specimen, th e presence or absence of 0 -4% oxygen, th e change from polycrystallm e to single-crystal specimens, or th e orientation of th e single crystals w ith respect to th e plane of cl form ation S G
^Preparation of Pure Gallium. Jam es I. Hoffman (J. Res. Nat. Bur. Stand., 1934 13 665-672 ; Research Paper No. 734).—A m ethod is described tor the preparation of pure gallium. The principal operations consist in (1) preparing a hydrochloric acid solution of th e m etal and extracting th e gallium, m olyb
denum, gold, iron, and thallium , together w ith small am ounts of other elem ents ; (21 precipitating antim ony, arsenic, bism uth, cadmium, copper, germanium , gold mercury, silver, and tin , and most of th e lead, m olybdenum, and rhenium , w ith hydrogen sulphide in an acid solution of th e ether e x tr a c t; (3) p recip itat
ing iron and thallium w ith sodium hydroxide and filtering ; (4) depositing the gallium electrolytically from th e alkaline f iltra te ; and (5) ehm m ating th e re
maining im purities by fractional crystallization of th e m etal. Indium and lead are th e most persistent im purities, b u t th e last traces can be rem oved by fractional crystallization. Gallium a t least 99-999% pure, containing only very faint traces of iron, lead, and calcium, and having a melting point of 29-780 ±
0-005° C., was obtained.—S. G. , , P o
* Freezing Point of Gallium. W m. F . R oeser and Jam es I. Hoffm an (J . Res.
Nat. Bur. Stand., 1934,13, 673-676 ; Research Paper No. 735).—The tem pera
ture of equilibrium between solid and liquid gallium was found to be 29-780 ± 0-005° C F our determ inations on 2 different lots of m etal (99-999 ^ Pu^e ) a “ yielded th e same result. Difficulties ascribed to th e undercooling and low therm al conductivity of th e gallium prevented a satisfactory determ ination from ordinary heating and cooling curves. The tem perature of equilibrium between th e liquid an d solid phases of th e m etal was obtained by m easuring th e tem perature of an intim ate m ixture of th e solid and th e liquid. I t was found th a t th e presence of th e oxide did not affect th e freezing tem perature, indicating th a t th e oxide is n o t appreciably soluble in th e m etal.—-b. G.
*The Anodic Passivation of Gold. W illiam Jam es S h u tt and A rth u r W alton (Trans. Faraday Soc., 1934, 30, 914-926).—F rom oscillograms of potential variations a t a n anodically polarized gold electrode th e m axim um lim iting current density (c0) for th e anodic dissolution of gold and th e tim e of p a s
sivation (T ) have been m easured in chloride, brom ide, an d sulphate solutions a t 25° C. and in A-hydrochloric acid a t 15°-65° C. The coulombs required to passivate th e electrode are given by th e expression (c — c0)T = A , where c is th e applied cu rren t density. I n halide solutions c0 an d A are approxi
m ately proportional to th e halogen ion concentration, b u t in sulphate solutions, if th e concentration of th e electrolyte is k ep t constant by vigorous agitation, K corresponds approxim ately w ith th e am ount of electricity required to produce a unim olecular oxide film on th e gold surface. A theoretical con
sideration of th e results leads to th e conclusion th a t anodic passivation takes place finally by th e form ation of a film of gold peroxide continuous w ith th e lattice stru ctu re of th e m etal.—A. R . P.
*The Anodic Passivation of Gold in Chloride Solutions. G. A rm strong a n a J . A. V. B utler (Trans. Faraday Soc., 1934, 30, 1173-1177).—I n un stirred chloride solutions th e tim es of passivation of gold electrodes are approxi
m ately proportional to th e concentration of chloride ion and are alm ost unaffected by replacing hydrochloric acid w ith potassium chloride. F o r tim es above 10 seconds (c — c0)T = K (cf. preceding a b stra c t); K is regarded as th e am o u n t of electrolysis required to produce a diffusion lay er th ro u g h
4 M etallurgical A bstracts
Vo l. 2which th e diffusion of chloride ions to th e electrode tak es place a t th e co n stan t ra te c0. The thickness of th e diffusion layer (8) in u n stirred an d stirred solu
tions is 1-5 — 4 x 10 2 cm. a n d 4 x 1 O' 4 cm., respectively. W hen o th er factors rem ain co n stan t K is proportional, an d c0 inversely proportional, to 8.—A. R . P.
*The Optical Constants of Polished and Sputtered Molybdenum Surfaces.
R . D. Summers (./. Opt. Soc. Amer., 1934, 24, 261-263).— The com puted reflectivity of sp u ttered m olybdenum varied w ith th e conditions of p re p a ra tion an d was considerably less th a n for th e m assive m etal. The results on th e massive m etal were n o t appreciably affected by polishing u n d e r kero
sene or while exposed to air.—R . G.
*The Magnetic Transformation Point of Heavily Cold-Worked Nickel. H . Q uinney (J. Inst. Metals, 1934, 55, 229-240 ; discussion, 240-245).—The Curie point of a ra th e r low-grade sam ple of comm ercial nickel was found to be 330° C., i.e. much lower th a n th e accepted value for pure nickel. A fter severe torsional overstrain th e Curie point on heating was raised to 365° C. b u t re tu rn e d to th e original value on cooling. The raising of th e p o in t was observed to be less on subsequent heatings, an d entirely disappeared a fte r a full anneal. I n the discussion C. J . Smithells referred to th e results ob tain ed b y R ansley an d him self on 99-9% nickel (J. Inst. Metals, 1932, 49, 287) an d suggested th a t th e effects observed by Q. were probably caused by im purities w hich w ould increase th e lattice distortion. O ther speakers endorsed th is suggestion. In reply, Q.
sta te d th a t th e nickel contained carbon 0-062, silicon 0-027, copper 0-08, iron 0-18, magnesium 0 08, manganese 0-30, sulphur 0-012, an d nickel 99-016% ; he agreed th a t th e effects of these im purities would p robably account for m any of th e observed results.—A. R . P.
*The Exact Measurement of the Specific Heats of Solid Metals at High Temperatures. XV.— A Redetermination of the Specific Heats of Palladium.
F . M. Jaeg er an d W. A. V eenstra (Proc. K . Alcad. Wet. Amsterdam , 193lj 37, 280-283).— [In English.] A redeterm ination of th e specific h eats of palladium showed th a t th e m axim a previously found in th e c — t a n d C — t curves were due to experim ental error. The cp — t curve proves to be nearly a stra ig h t fine, although a slight increase in th e slope above 1125° C. is evident. N o indication of a n allotropic change is observed. The specific h e a t cp is given b y : cp = 0-058378 + 0-120548 x 1 0 ^ + 0-258 x and th e atom ic h e a t by Cp = 6-2288 + 0-12862 x 10 H + 0-27528 X lO“7«2. The value 3 R cal. is exceeded for Cp a t — 150° C. a n d for Cv a t — 120° C. S. G.
*The Action of an External Electrical Field on Hydrogen-Charged Metals [Palladium]. T. F ranzini (A tti R . Accad. Lincei (Rom a), 1934, 19, 584- 588; C. Abs., 1934, 28, 7098).—A palladium w ire, electrolytically charo-ed w ith hydrogen in a sodium hydroxide solution, was exposed to th e fielcf of a p ro to n rectifying transform er a t 25 kv. The resistance of th e wire was m easured w ith a W heatstone bridge. A positive p o ten tial of 15,000 v.
u n d er a vacuum (10 4 mm .) caused a v ery sm all loss of hydrogen, an d a flow of c u rren t of less th a n 0-1 m illiam p. A negative p o ten tial of th e sam e m ag
n itu d e, how ever, discharged a b o u t | of th e adsorbed gas in 15 m inutes a n d gave a c u rren t of 10-12 m illiam p., because th e pro to n s were to rn aw ay from th e palladium wire, an d w ith d raw n by th e high vacuum . S. G.
*The Catalysis by Palladium of the Union of Hydrogen and Oxygen. A New Phenomenon of Contact Catalysis. D. L. C hapm an an d G. G reeorv IPm r Roy. Soc., 1934, [A], 147, 68-75).—The m echanism of th e catalysis of th e union of hydrogen an d oxygen by palladium is m ainly one of alte rn a te oxidation of m etal an d reduction of th e oxide. A dsorbed hydrogen does n o t react appreciably w ith oxygen a t room tem perature. B y suitable tr e a t m ent palladium can be rendered tem porarily in e rt as a c a ta ly st of th e reaction betw een hydrogen an d oxygen This tem p o rary inertness is a ttrib u ta b le to a com pact layer of adsorbed hydrogen.—J . S. G. T.
1935
I . — Properties o f M etals
*The Exact Measurement of the Specific Heats of Solid Substances at Higher Temperatures. XVI.— The Specific Heats of Metallic Thorium and of Thorium Dioxide Between 20° and 1400° C. F . M. Jaeger and W. A. V eenstra (Proc.
K . ATcad. Wet. Amsterdam, 1934, 37, 327-332).— [In English.] The mean specific h eat of thorium has been m easured between room tem perature and 1200° C. The atom ic h e a t increases continuously from 8-235 a t 300° C. to 11-785 a t 1200° C —S. G.
♦Resistivity of Zinc Crystals. W . J . Poppy (Proc. Iowa Acad. Sci., 1932, 39, 217; C. Abs., 1934, 28, 6602).—I n an a tte m p t to settle th e discrepancy betw-een th e resistivity m easurem ents of Bridgm an on th e one hand and of Tyndall and Hoyem (J. Inst. Metals, 1931, 47, 645) on th e other, single zinc crystals of 1 cm .2 cross-section and 10 cm. long were grown and measured.
The results agree w ith those of Tyndall an d Hoyem . P resent indications are th a t certain anom alous crystals (i.e. n o t tru ly single) have abnorm ally low resistivities and show great sensitivity to slight strain .—S. G.
♦Influence of a Grain Boundary on the Deformation of a Single Crystal of Zinc. R ichard F . Miller (Metals Technology, 1934, (Oct.), A .I .M .M .E . Tech.
Publ. No. 576, 1- 9).—F rom tensile experim ents a t 180° C. on single-crystal rods of zinc term inated b y a transverse grain boundary adjoining^ poly
crystalline m etal it is shown th a t th e influence of th e grain boundary is con
fined to glide planes which it directly intersects and. is composed of two d istinct p arts. I n th e first p a rt, th e glide layers are held motionless and th e m axim um e x ten t of th is influence is th e distance p , such th a t d = p /[ta n l(a + a')] + j)/[ta n (90° — a)], where d is th e original diam eter of th e rod, a is th e original angle of th e basal planes to th e axis of th e rod, and a ' is their final angle thereto. I n th e second p a rt, th e glide layers have passed through a flexure and slid over one another to a small e x ten t b u t n o t sufficient to form a uniform b a n d ; th e m axim um e x te n t of th e influence of th e grain boundary is q, where q = d cos a ' . cos (a — a')/sin a. H ence th e grain- boundary influence varies regularly w ith th e size of th e boundary, th e am ount of deform ation, an d th e du ctility of th e crystal.—A. R . P.
♦Influence of Chemically- and Mechanically-Formed Notches on Fatigue of Metals. D unlap J . McAdam, J r ., and R obert W. Clyne (J. Res. N at. B ur.
Stand., 1934,13, 527-572 ; Research Paper No. 725).—An introductory section discusses th e im portance of stress concentration due to notches, as a cause of failure in service. Resistance of a notched specimen to fatigue and to im pact m ay depend on entirely different properties. The influence of notches on fatigue is considered in th e present paper. In section I I th e effect of chemically- formed notches is considered, a tten tio n being confined to th e influence of p i t t ing caused by stressless corrosion. Relationship betw een tensile stren g th and th e % decrease in th e fatigue lim it of steels and alum inium alloys is illu strated by composite curves, each of which is presum ed to represent th is relationship for a notch of fairly constant effective sharpness. The 3-dimensional relation
ship between corrosion tim e, % damage, and th e tensile strength is illu strated and discussed. The general object of section I I I is to determ ine w hether com
posite curves of sim ilar form m ay be obtained by a stu d y of experim ental d a ta obtained by a num ber of investigators w ith mechanically-form ed notches.
The fact th a t such graphs have been obtained, each representing th e influence of one form of n otch on one k in d of m etal, confirms th e conclusion th a t a stressless corrosion graph of th is type represents th e influence of a notch of fairly con
sta n t effective sh arp n ess/ Reasons are discussed for th e deviation of individual results from th e ideal composite curve for a m echanically formed notch. In section IV is considered th e relationship betw een notch sensitivity (as m easured by % damage) and other properties of metals. The properties considered are : hysteresis, d u ctility , an d w ork-hardening capacity. Evidence is presented th a t scatter of individual results in a com posite graph of th e type used is due
6 Metallurgical Abstracts
Vo l. 2largely to differences in tensile w ork-hardening capacity. E vidence is also presented th a t notch sensitivity, while depending som ew hat on elastic hysteresis, depends largely on w ork-hardening capacity. T he influence of notches in dim inishing th e advantage of superior stren g th is d ealt w ith in section V. A bibliography of 33 selected references is appended.— S. G.
*Elasticity. A rth u r Cecil V ivian (Inst. Civil Eng. Selected Eng. Papers, 1934, (150), 1-32).—A n extension of H ooke’s law to enable m ore ex act use to be m ade of m aterials for constructional purposes is proposed. E lasticity is tak en to be th a t p ro p erty which determ ines th a t a m aterial will com pletely or partially resum e its original shape w hen th e applied force is rem oved, and H ooke’s law is w ritte n : stress = { ( J - + l ) — l | • / , where S is elastic strain, S m u ltim ate elastic tensile strain , J a form facto r denoting elastic character, an d f u ltim ate tensile stress. W hen J = 2, th is reduces to H ooke’s law. Exam ples of th e application of th e m ethod are given.—J . C.
*Elastic Failure of Thick Cylinders. H arris B ooth (In st. Civil Eng. Selected Eng. Papers, 1934, (138), 1—40).—The conditionsof failure are exam ined for thick cylinders subjected to in tern al pressure, to ra d ia l tem p eratu re gradient, and (for cylinders closed a t one end) to b o th in te rn a l an d external pressures.
I t is shown th a t no stresses are induced in a th ic k cylinder subjected to a uniform longitudinal tem p eratu re g radient.—J . C. C.
*On Hardening Phenomena in Pressed Metal Bodies. W . T rzebiatow ski (Z.
physikal. Chem., 1934, [B], 24, 75-86).—Bodies m ade b y pressing very finely- divided gold an d copper powders a t pressures u p to 30,000 atm . show consider
able hardening effects, characterized b y a broadening of th e interference lines in th e rontgenogram and a high degree of dispersion ; no tru e te x tu re is, how
ever, produced. The hardness values obtained are m uch higher th a n those observed on e ith e r m etal after severe w orking ; th is is a ttrib u te d to th e very fine crystal stru ctu re of th e pressed bodies. T he fall in hardness w hich occurs on annealing is produced by recovery and recrystallization phenom ena.—K. S.
♦On the Problem of the Electrical Conductivity of Synthetic Metal Bodies.
W . Trzebiatow ski (Z. physikal. Chem., 1934, [B], 24, 87-97).— Compared w ith massive m etals, pressed bodies m ade from m etal powders show peculiar anom alies in th e electrical conductivity. F or pressed bodies of gold and copper th e tem p eratu re coeff. of resistance is positive u p to 100° C., negative betw een 100° and 300° C., an d positive again a t higher tem peratures ; th is behaviour is a ttrib u te d to gas films and to recrystallization phenom ena, w hich have been confirmed by dilatom etric m easurem ents.— K . S.
♦Researches on the Thermal Conductivity of Metals (Wire or Tape) at High Temperatures. M. C onard (Aérotechnique (Suppt. to Aéronautique), 1934, 12, 26-27).—A m ethod is briefly described an d illu strated in w hich th e wire is m ounted in an evacuated tu b e betw een 2 ta p e s so t h a t i t can be heated by a cu rren t passed eith er th ro u g h it or th ro u g h th e supporting tap es alone.
— J . C. C.
A Classical Model of a Ferromagnetic Material and Its Subsequent Quantiza
tion in the Region of Low Temperatures. G. H eller a n d H . A. K ram ers (Proc. K . A kad. Wet. Amsterdam, 1934, 37, 378-385).— [In G erm an.] The classical model of a ferrom agnetic m aterial is defined ; only w hen conceived in term s of a space lattice does th e model indicate th e occurrence of ferro
m agnetic satu ratio n . Q uantization of th e model produces th e formulae of Bloch an d Muller exactly.—J . S. G. T.
♦Drift of Magnetic Permeability at Low Inductions after Magnetization R aym ond L. Sanford (J. Res. N at. Bur. Stand., 1934, 13, 371-376; Research Paper No. 714).—The m agnetic perm eability of ferrom agnetic m aterials a t low values of induction depends on th e tim e which elapses betw een dem agnetization a n d testing. The change m ay be of th e order of 10 or 12% . I n order to
1935
I I . — Properties of Alloys 7
obtain consistent and reproducible results in testing a t low inductions, a period of from 18 to 24 brs. should elapse after dem agnetization before th e te s t is
made.—S. G . ______________
I I — PROPERTIES o f a l l o y s
*fnrrelation of Equilibrium Conditions in Binary Aluminium Alloys. W. L.
Fink and H. R . Freche (Metals Technology, 1934, (Oct.), A .I .M .M .E . Tech.
Publ No. 580 1-14).—The results obtained previously for th e equilibria a t the alum inium end of binary system s of th a t m etal w ith other m etals of hig pu rity have been analyzed m athem atically, and th e solid solubility and hvnereutectic liquidus curves are shown to be in agreem ent w ith those deduced K m the therm odynam ic equation log, s ' = - L I R T + C. where x ‘ A s th e mol. fraction of alloying elem ent, L th e molal h eat of solution, R th e g constant, T th e absolute tem perature, and C th e integration constant.
The systems w ith magnesium and w ith magnesium silicide, however, do not obev th is rule. A straig h t line is obtained by joim ng th e points obtained bv plotting th e logarithm of th e eutectic lowering against th e logarithm ot th e atom ic-% of solute in solution a t th e eutectic tem perature, th e point for manganese being th e only one n o t n ear th is line. The reciprocal of the slope of th e solubility line for all binary system s is a linear function of the logarithm of th e concentration of th e solute, and therefore th e slope of the solid solubility curve for any binary alum inium system can be determ ined from any point on i t by m eans of th e expression .
1 _ T log x ' _________ T ________ —A. R . P . S ~ 0-0003T — 1 + 0-417 — 0-000125T
♦Effect of Quenching Strains on Lattice Parameter and Hardness Values of High-Purity Aluminium-Copper Alloys A rth u r Phillips and R M Brick (Metals Technology, 1934, (Sept.), A .I .M .M .E . Tech. Publ. No. 563 1-19) C opper-alum inium alloys m ade from very pure m etals m ay show an abnorm ally large lattice param eter w hen quenched from th e solid solution range due to strain resulting from quenching stresses. The param eter is greate the more severe th e quench, th e greater th e diam eter of th e specimen up to 0-5 in., and th e higher th e copper content of th e solid solution, l h e m ax i
mum a«e-hardening capacity a t 20° C. is shown by drastically quenched alloys w ith 5-4% copper; during ageing there is first a slight decrease m the lattice param eter, b u t th e constant value ultim ately obtained is sufficiently high to indicate th a t p a rtia l precipitation is th e cause of th e observed hard ing The initial decrease in param eter is a ttrib u te d to gradual relief of stres . W hen th e quenching is only ju s t sufficient to retain th e m etastable solid solution w ithout producing severe quenching strains th e alloys do n o t exhibit any hardening after 30 days a t 20° C., w hich suggests th a t th e presence of these strains is essential for hardening to occur a t room t e m p e r a t u r e P r e cipitation of CuAl2 a t 275°-325° C. is more rap id th e greater th e quenching strain an d th e greater th e degree of su p ersatu ratio n ; w hen th e a llo y s a re acrain quenched a fte r precipitation is com plete th e param eter of th e residual solution is greater th a n th a t of pure alum inium , b u t when th e y are air-cooled or quenched in boiling w ater a norm al reaction curve is obtained. R eheating a t th e precipitation tem p eratu re followed b y a drastic quench again p ro duces a distended lattice, which cannot, therefore, be due to stra in induced by th e precipitation process. M axim um hardness after ageing a t 275 300° C. is obtained w hen precipitation is p ractically com plete. A. K. .
♦Ternary Diagram of the Aluminium-Copper-Silicon System. K an ji M atsu
yam a (K inzoku no K enkyu, 1934, 11, (10), 4 6 1 - 4 9 0 ) .- [ I n Japanese.] The diagram s of th e b inary system s alum im um -copper, copper-silicon, an d
alum inium -silicon have been carefully redeterm ined b y means of therm al analysis, electrical resistance determ inations, an d microscopic exam ination.
The alum inium -copper-silicon system was th e n investigated from m elt to room tem perature, an d th e te rn a ry diagram of th e whole system was con
structed.'—S. G.
*The Influence of Pickling on the Fatigue-Strength of Duralumin. H . S utton an d W. J . T aylor (J. In st. Metals, 1934, 55, 149-158; discussion, 158-164).—
The effect on th e fatigue lim it of D uralum in in W ohler-type fatigue te sts of th e following pickling treatm en ts has been determ ined : (A) 2 | m inutes in 10%
caustic soda solution a t 60°-70° C., rinse, 1 m inute in 10% nitric acid containing 10% of sulphuric a c id ; ( II) 2 m inutes in a solution containing 10% each of nitric and hydrofluoric acids ; (C) 3 m inutes in a 4 : 1 m ixture of 10% sulphuric and hydrofluoric acids, rinse, 1 m inute in 50% nitric acid. The percentage decreases in th e fatigue lim its observed were (A) 31% , (B) 15%, (C) 6% ; im mersion in boiling w ater after th e pickling tre a tm e n t reduced these decreases t ° ( A ) 10% and (G) 3-8%. T reatm ent (A) produces a rough serrated surface, an d tre a tm e n t (C) reveals th e m acrostructure of th e alloy an d is, therefore, suitable for th e exam ination of the alloy for defects in m anufacture. Rem oval of th e pickled surface layer b y m achining com pletely elim inates th e effects of pickling on th e fatigue iim it, indicating, as suggested by 1). Hanson and by 1. 6r. Slater in th e discussion, th a t pickling produces a weakening of th e surface layer eith er by gas adsorption or by setting up internal stresses, or th a t inter- crystallm e p enetration of th e pickle occurs and induces corrosion-fatigue (suggested by E . Seligman). E . Wood sta te d th a t for commercial w ork a m ixture of sodium fluoride and sulphuric acid was preferable to hydrofluoric acid for pickling light alloys.—A. R . P.
♦Studies on the Decomposition of Supersaturated [Solid Solutions] in Light Metal Alloys. E . Schmid and G. Siebel (Metallwirtschaft, 1934, 13, 765-768).
— I h e decom position of quenched alloys of m agnesium w ith zinc and alum i
nium a t 218° C., and of alum inium w ith m agnesium a t 218° and 155° C. has been followed by X -rays. The precipitation takes place th e m ore rapidly th e greater th e degree of supersaturation of th e solid solution and more slowly w ith single crystals th a n w ith polycrystalline aggregates. I n zinc-m agnesium alloys and in single crystals of alum inium alloys th e composition of th e solid solution decreases steadily from th e beginning to th e end of th e reaction. In polycrystalline alum inium -m agnesium and m agnésium -alum inium alloys th e in itial and final concentrations are close together. The changes in th e m echani
cal properties follow closely th e progress of precipitation.—v. G.
Electrometallurgical Research and Its Relation to the Grand Coulee Power Development (Some Facts on the Ultra-Light Structural Alloys of Magnesium and Alummium). A. E. D rucker (State Coll. Washington, M et. lies B ur Inform ation Circ. No. 8, 1934, 6 pp.).— S. G.
SUumin-Gamma J D ornauf (A lu m in iu m , 1934, 17, 26-31).—See also M et. Abs., 1934,1,414. Silum m -y is th e eutectic silicon-alum inium alloy con
taining sm all additions of m agnesium and m anganese an d modified by th e usual sodium tre a tm e n t ju s t prior to pouring. A fter quenching from ju s t below the solidus th e alloy can be hardened by an ageing treatm en t. Sand-castings have n m n9(n CSV 8? " 100; a yield-point of 18-25 kg./mm.*, a tensile strength l i f kg-/mm and an elongation of 4r-0-5% ; th e corresponding values for ch in -castm g sare 85-110 20-28, 26-32, and 1-5-0-5, and for die-caftings 110- 130, , 30 37, and 1-1-5. The alloy finds extensive use in th e m anufacture of housings for aero- and autom obile engines and sim ilar in tricate castings where lightness, strength, and a high yield-point are desirable.—A R P
- - ^f j l echani cal Properties of Copper-Rich Alloys Due to the Grain- Refinement by the^entectic Reaction. Ju -n Asato (K inzoku no K e n h m ,
’ U > (8). 3 6 5 - 3 7 6 ) H > Japanese.] The m echanical properties such as
8 Metallurgical Abstracts
V o l.2
1935
I I . — Properties of Alloys 9
B rinell hardness, tensile strength, elongation, yield-point, and lim it of pro- portionality of some copper-rich alloys were determ ined to show how these properties are modified by grain-refinem ent caused by peritectic reaction^.
♦Crystal Densities of Industrial Brasses from X-Ray Data. E . A. Owen and Llewelyn Pickup (.7. Inst. Metals, 1934, 55, 215-222; discussion, 223-228).—
The density of homogeneous alloys of copper and zinc in th e a, a + 0 , an d 0 regions have been calculated from th e lattice param eter as measured by X -rays, and th e results obtained are shown to be superior to those obtained by weighing in air and w ater, since th e y are unaffected b y porosity, cold-work, and grain- size, as well as by h eat-treatm en t in th e case of pure a- or pure 0-alloys. i he density of a-alloys is no t a linear function of th e composition, b u t th a t ot 0- and th a t of (a + 0)-alloys can be ta k e n as linear to a high degree of accu racy ; a t the phase boundaries, however, discontinuities in th is relation occur, th e values obtained are tab u lated and th e effect of quenching tem perature on the density of duplex alloys is shown graphically.—A. R . P.
*Gold-Chromium Resistance Alloys. Jam es L. Thom as (J. Res. N at. isvr.
Stand., 1934, 13, 681-688; Research Paper No. 737).—The addition of from 1-6 to 2-4% or more of chrom ium to gold produces alloys having very sm all tem perature coeff. of electrical resistance. In particular, 2-1% chrom ium in gold gives an alloy whose resistance has been m ade independent of tem perature, to a few p arts in 10 million, over a t least th e interval 20°-30° C. These alloys are also exceptionally stable in resistance. They have, however, a th erm o electric power against copper w hich is 3 or 4 tim es as large as th a t of M angamn.
The preparation and h eat-treatm en t of some of these alloys are described.^
♦Age-Hardening of Lead Alloys. H. H ariba (Sumitomo-Densen Iho, 1934, 1, (2), 49-57; C. Abs., 1934, 28, 7229).—Lead-calcium alloys containing 0 -02% calcium undergo age-hardening; th e m axim um hardening effect is a t 0-1% calcium. The rate of change in hardness and in electrical resistance of lead containing calcium on ageing varies according to th e calcium c o n te n t;
the volume of lead containing calcium contracts a little on age-hardening.
In lead containing antim ony expansion is shown.—S. G.
Bearing Metals in Use on the Railways of the U.S.A. [Satco Metal]. lAr,J W itte (Organ Fortschr. Eisenbahnwesens, 1934, 89, 400-402).— See Met. Abs.,
1934, 1, 416.—P. M. C. R . T
♦Solubility of Carbon in Iron-Manganese-Silicon Alloys. C. H. lie rty , j r . , and M. B. R oyer (U .S. Bur. M ines, Rept. Invest. No. 3230, 1934, 22 pp.).— I h e solubility of carbon in iron-m anganese alloys up to 75% manganese, in iro n - silicon alloys u p to 50% silicon, an d in iron-m anganesc-silicon alloys w ith a 4—10 : 1 manganese-silieon ratio has been determ ined a t 1300 -1700 L., an a th e results are shown in tables and graphs. Manganese, having a carbide- stabilizing action, increases th e solubility of carbon, whereas silicon, having a graphitizing action, has th e opposite effect, only 0 -1% carbon being retained in solution in th e 50 : 50 silicon-iron alloy. A 3-page table is given showing th e carbon solubility a t 1300°, 1500°, and 1700° C. in alloys contaim ng 0-80 /0 manganese and 0 -2 0 % silicon in 5% steps. The bearing of th e results on th e composition an d use of these alloys as steel deoxidizers is discussed. A. R. P.
♦On Anomalous Properties of New Magnetic Materials [Copper-Nickel- Iron Alloys]. M artin K ersten (W iss. Veroff. Siem ens-Konzem , 1934, 13, (3), 1- 9 ).—The m agnetic properties of 45 : 55 nickel-iron alloys w ith additions ol 0 , 3, 6, 9, 12, and 15% copper have been determ ined after annealing, in th e form of 3 mm. wires, a t 900° C. for 2 hrs., slowly cooling, and rolling to strips 0-08 mm . th ic k w ithout fu rth e r annealing. W ith o u t addition of copper th e alloys give a norm al m agnetization curve an d a rem anence of ab o u t 50% of th e s a tu r a tio n m agnetization, w hereas th e 9% copper alloy gives a linear m agnetization
10 M etallurgical Abstracts
Vo l. 2 curve and a rem anence of only 6% , which, however, is increased alm ost to 100%if th e alloy is subjected to a tensile stress of about 60 k g ./m m .2 in th e direction of th e magnetizing field. Analysis of th e m agnetic stresses in these alloys indicates th a t th e stress rises sharply w ith increasing copper c o n te n t; anneal
ing tests indicate th a t th is increase in stress is due to precipitations sim ilar to those which occur in precipitation-hardening. V ery high rem anence values approaching closely to th e satu ratio n m agnetization can he obtained in the 12 and 15% copper alloys by annealing th e hard-rolled strip a t 600° C. A. P.
*Torsional Moduli Variations of Spring Materials with Temperature [Konell Joseph W. Ludewig (Trans. Am er. Soc. Metals, 1934, 22, 833-860).—The behaviour of springs a t elevated tem peratures involves knowledge of th e values of th e modulus of rig id ity and proportional lim its of m aterials a t such tem peratures. A sum m ary of previous w ork on th e v ariatio n of th e modulus of rigidity w ith tem perature, and on th e behaviour of springs a t elevated tem peratures is given. The torsional moduli of a num ber of m aterials are plotted against tem perature, and in accordance w ith th e procedure outlined in th e paper th e following results were o b ta in e d : (1) M aterials m aintaining highest absolute value of th e m odulus of rig id ity u p to 450° P . (232° C ) are high-speed steel, stainless (cutlery) steel, and Konel. (2) M aterial m ain tain ing highest absolute value of th e modulus of rigidity up to 985° P . (529° C.) is high-speed steel. (3) M aterial showing lowest absolute value of th e modulus ot rig id ity a t all tem peratures is carbon spring steel. (4) The rem aining m aterial tested was Silcrome steel. A discussion of th e factors found in s p rin t formulae and behaviour under tem p eratu re variations is included. S. G.
Applications of Silicon. J . W. D onaldson (Metallurgia, i •+ 1- J ' • uses siliphh as a n alloying m etal are considered an a its applications in steels, cast irons, corrosion-resisting alloys, an d non- ferrous alloys are discussed. The non-ferrous alloys referred to are th e silicon-alum im um alloys of th e D uralum in, R .R . alloys, A lpax (Silumin) W L hyPoeutf otlc alum inium -silicon alloy ty p e s ; th e copper-silicon alloys’
both silicon-bronzes and silicon-brasses, an d nickel-silicon alloys. J . W . D.
Recent Development in Main and Connecting-Rod Bearings. Stanw ood w !
¡sparrow (Soc. Automotive Eng. Preprint, 1934, Ju n e, 7 p p .; an d (sum m ary) Autom otive I n a . 1 9 3 4 , 70 7 7 2 -7 7 3 ).-E v id en ce is given w hich indicates a t hexing and fau lty bonding are n o t th e prim ary causes of cracking in m am an d connecting-rod bearings of autom obile engines, b u t th a t cracking is produced by a tangential force betw een th e journal an d th e bearing a t spots where th e oil-film is inadequate to p revent m etal to m etal contact. A minim um thickness of 0 03 in. of B a b b itt m etal is recom m ended, an d under- cu mg has been found to extend th e life of th e bearing since i t prevents the cracks from spreading an d perm itting the B a b b itt m etal to escape. C opper- lead bearings (lead 45, nickel 2, copper 53% ) crush as readily as B a b b itt metals, an d m etal to m etal contact produces a lead film w hich has sufficient lubricating prevent seizing; failure of copper-lead bearings occurs b y disinte
gration of p arts where i t is difficult to m aintain an oil-film or w hen a n unsuitable discussed A R p Catl° n ° f bearings an d th e effects of “ d i r t ” are briefly i The Improvement of White Bearing Metals for Severe Service : Some General Considerations. D. J . M acnaughtan (J. In s t. Metals, 1934, 55, 33-47).—
d evelopm ent in th e in tern al com bustion engine is im posing increasingly severe conditions on bearings. Consideration is given to th e theoretical functions of a n ideal w hite m etal, and th e m anner in w hich th e stresses produced in service ten d to cause failure by cracking. Since th e norm al action of th e stresses is compressive special a tte n tio n is given to th e tension stresses w hich are shown to lower th e fatigue range of th e m etal an d to open up incipient cracks. Based on th is analysis th e mechanism of crack form ation is discussed. The following
1935
I I . — Properties o f Alloys 11
directions in w hich im provem ent in service behaviour m ay be secured are considered : (1) dim inishing th e intensity of the stresses in th e m etal by m odi
fications in (a) certain features in d esig n ; (b) th e m aterial used for th e lin e r;
(2 ) increasing th e fatigue-resisting properties of th e w hite bearing m etal, in respect to which results obtained in prelim inary investigations of th e fatigue properties of high tin -an tim o n y -co p p er alloys w ith and w ithout addition of a furth er elem ent are given.—D. J . M.
*The Behaviour of White Bearing Metals when Subjected to Various Deforma
tion Tests. Introduction. ---(J. Inst. Metals, 1934, 55, 49-50).—The scope of th e investigation and compositions of th e m aterials used are given. The results of th e research are described in 3 p arts ; for abstracts see below.-—S. G.
*The Behaviour of White Bearing Metals when Subjected to Various Deforma
tion Tests. Part I.—Indentation Tests. A. S. K enneford and H ugh O’Neill (J. Inst. Metals, 1934, 55, 51-69).—The effect of viscous flow, ageing, and pro
longed heating on th e resistance to indentation of tin- and lead-base bearing m etals has been investigated. Flow tests w ith a 120° steel cone a t 19° and 96° C. show th a t B ab b itt m etal containing 1% cadm ium or 2% nickel, or a lead-alkali bearing m etal, give b e tte r indentation results th a n a plain B ab b itt alloy. The hardness of th e different m etallographic constituents of bearing metals and th e ir softening on heating to 100° C. were m easured by scratch and micro-indentation tests. The m atrices lose 40-45% , and th e cuboids 20% of th e ir hardness, b u t th e cuboids in a B ab b itt rem ain som ewhat h arder th a n those in a lead-base alloy. Two new simple tests are suggested. In th e first a lubricated 60° conical casting of th e alloy is flattened under 100 kg. load for 30 seconds, and th e Mallock hardness num ber determ ined. By increasing th e duration of loading a flow index m ay be m easured on lines sim ilar to “ H a r
greaves’ analysis.” Then, by compressing u n til cracks appear on th e extruded edge, th e d u ctility of th e specimen and its cracking stress m ay be measured.
A t room tem peratures th e lead-base alloys show relatively low ductility, and this agrees w ith th e ir low w ork-hardening capacity as determ ined by specially conducted ball tests and repeated im pact te s ts w ith th e scleroscope. The second m ethod employs an in stru m en t sim ilar to th e H erb ert pendulum , and measures th e dam ping effect. I t m ay n o t only be used to give rapid indications of hardness a t different tem peratures, b u t is also sensitive to th e effect of dif
ferent lubricants.—A. S. K .
*An X-Ray Examination of the Phases in Babbitt Metal, and of the Age- Hardening of Cast Lead-Alkali Alloy. G. S. F am h am (J. Inst. Metals, 1934, 55, 69-70).—A ppendix to a paper b y K enneford an d O’N eill (see preceding abstract). An alloy of th e composition SnSb after annealing for 1 week has a structure of th e NaCl ty p e w ith a = 4-099 A. The presence of th is compound in B ab b itt m etal has been confirmed by X -ray tests. The needle constituent of B ab b itt m etal has been isolated by liquation an d its composition proved to be CuSn or th e -/¡-phase of th e copper-tin system . X -ray exam ination of a sodium -calcium -lead bearing alloy in th e newly cast and in th e aged condition shows th a t th e cast alloy consists of tw o phases, one of w hich changes w ith age
ing w hilst th e o th er does n o t; th e la tte r is face-centred cubic w ith a = 4-889 A., an d is probably CaPb3. The form er is a su p ersatu rated solution of sodium in lead w hich deposits a sodium-rich phase (possibly N a2P b 8) on ageing.—A. R . P.
*The Behaviour of White Bearing Metals when Subjected to Various Deforma
tion Tests. Part II.—Tensile Tests. R . A rrow sm ith (J . Inst. Metals, 1934, 55, 71-76).—The tensile properties of w hite m etal specimens, prepared by gravity die-casting an d w ith o u t any m achining, have been determ ined a t room tem p era
tu re on a Hounsfield “ Tensom eter.” V arious casting conditions were exam ined for each alloy. B a b b itt m etal w ith additions of cadm ium gave th e highest values of lim it of proportionality an d u ltim ate stress. The greatest d u ctility was obtained from an alloy containing 89% of tin .—R . A.
12 Metallurgical Abstracts
Vo l. 2Ï Behaviour of W hite Bearing Metals when Subjected to Various Deforma-
„ P art HI-—Pounding Tests. H . Greenwood (,J . In st. Metals, 1934, oo, i /-» / A modified form of th e Stanton im pact te s te r suitable for th e te s t
ing oi w hite m etals by pounding a t different tem peratures is described. R e
sults on cylindrical specimens are given, and th e u n su itab ility of th is type of test-piece is shown. The use of bearing-shaped specimens w ith a cylindrical indenter is described. R esults are recorded for 8 different w hite-m etal bearing
a cast under various conditions, an d tested a t 18°, , an o O. A B a b b itt m etal w ith an addition of cadm ium gave th e greatest resistance to pounding.—H . G.
„ Jom t Discussion [on the Im provement of W hite Bearing Metals for Severe
• j 1C?1‘ , (•/. Inst- Metals, 1934, 55,88-113). See 6 preceding a b stracts.—
A . J . M urphy and J . Cartland expressed th e opinion th a t failure of bearings was irequently due to stresses set up by th e different contraction of th e lining and ell on cooling and n o t prim arily to the form ation of a b rittle tin -iro n compound
^ C-]U^ 0n . m tw o m etals‘ K Chadwick sta te d th a t, w hen a bearing is rm rW 1? ’ u ? ls ln a cold-worked condition in w hich th e ra te of creep weÎe viven ' v" 1 Wh°n th e m etal WaS Cast ’ fiSUres an d curves r n thlS hehavl0ur- He had found th a t addition of cadm ium
? prevents cracking during cold-rolling by suppressing th e th e S u r e Of b ^ ° j T • crackinS commenced. H . Sutton considered th a t addition of t r i dUo t0 fa tigue-cracking and stated th a t resneef all° ys im Pr°ves th e ir behaviour in th is cadm ium W l, n'S Sai<4 Ï annea,m g im proves th e stress conditions in s t e e ^ o r b i f 1 m+g tll6Se all° yS can now b(? readily cast on to
o w i m nCrn t0 glW Vah;CS ° f 6'5 to n s/in -2 in th e shear of bond te s t and to w ithstand 15 m illion reversals of stress a t a stress of 18-9 to n s/in 2 on th e th ere f c ? definite f t ’1 R ' W \ Bailey Save a m athem atical proof th a t H N , » u K u 10n betwfe?n m denter flow tests and tensile creep tests.
II. N . Bassett described a case of failure of a 50 : 38 : 10 : 2 tin -le a d -a n tim o n v - copper alloy used as a bearing m etal in th e axles of railw ay wagons O ther m e t^ eb l P forw ard various theories to account for th e cracking of B ab b itt m etal bearings subject to high duty, and Macnaughtan, Kenneford, O’N eill and S f f f i S S a S * *5? dis.cusfi° n ’. critically reviewed a l/th e^ e t h e o r i e s
b ~ ™ g » . W s , a n d p u t f o ™ r i ,u g g ,,t i„„s
*Some Properties of Tin Containing Small Amounts of Silver, Iron Nickel or i i‘- °n, E- J . Sandford, and H. Stevens (J. Inst. Metals 1934 55 115-131 ; discussion 1 3 1 -1 3 3 ).-T h e tin-rich ends of th e s i l 4 " n ic k e l-tS ’ a n d copper tin equilibrium diagram s were investigated. W ith th e first th é eutectic occurs a t 3-5% silver, a t 221-3° C. ; w ith th e second, a t 0-18% nickel
are ti “ PvOtb th e l i l "I’®8 n °n 7nry uPprcClably from th e m elting point of pure t i n , w ith th e last, between 0-70 and 0-75% copper a t 226-9° C The solid
n “ o K e y i s ; " c " “Tr r
m g to u Ub/0 a t 210 C. The solid solubility of nickel is less th a n 0-005°/ and t h a t of copper less th a n 0 -01% a t 220° C. The m ethod of m S g a S i o k s to tin is discussed ; no p articu lar difficulties are m et w ith in th e case Sf silveT iron
S a T ni°kkL The]mflnence of additions of these m etals on th e t ’ensilé stren g th of tin is discussed. A great increase produced by quenching silv er-tin alloys is n o t perm anent a t room tem perature, w hilst w ith th e o th er 3 allovs quenching has no effect. A dditions of iron above 0 -4°/ are w ithout off t found Ahckd u Ï to 0 -3^ m o d ^ inCr6aSe ° f 4° % in tb e tensile s t r e n g t h ^
a d ffittn s“ no ^
stren g th after all h eat-treatm en ts investigated.' ° Silver refi^esT hegrain o T tirf b u t does n o t p revent gram -grow th a t high tem peratures. The a d d S o n of iron
above 0-05% or of nickel above 0-06% prevents such grain-grow th, although below these compositions germ ination takes place. 0-35% and more of copper prevents recrystallization of cold-rolled tin a t room tem perature, b u t annealing a t tem peratures from 110° C. upw ards produces larger grains th a n in alloys of slightly lower copper content.—I). H .
^Studies of Phase Changes During Ageing of Zinc-Alloy Die-Castings. I.—
Eutectoidal Decomposition of Beta Aluminium Zinc Phase and Its Relation to Dimensional Changes in Die-Castings. M. L. F uller and R. L. W ilcox (Metals Technology, 1934, (Sept.), A .I.M .M .E . Tech. Publ. No. 572, 1-17;
and (abstract), Iron Age, 1934, 134, (15), 30-31).—On ageing th e quenched /5-aluminium-zinc alloy a t 0° C. decomposition into a + y is complete in 31 m inutes and th e tem perature rises to 84° C .; th e corresponding figures for ageing a t 20° C. are I f m inutes an d 108° C., and a t 50° C. 1|- m inutes and 133° C. A fter quenching from 350°-375° C. in w ater a t 20° C., th e 20%
alum inium -zinc alloy decomposes into a + y in 1J m inutes w ith an increase in tem perature to 99-3° C .; w ith 1% copper th e tim e required is 58 m inutes and th e tem perature reaches 78° C., an d w ith 0-1% magnesium decomposition sta rts in 3 days a t 20° C. and is completed in about 35-40 days a t 20° C., b u t a t 100° C. decomposition is complete in 1 day. The change in length on ageing th e jB-alloy w ith 0-1% magnesium is 0-29%. The jS-phase in com
mercial zinc-base die-casting alloys w ith 0 '3 % copper and 0-04% magnesium is completely decomposed in less th a n 1 d a y ; th is m ay be due to th e slower rate of cooling or to th e acceleration of th e decomposition by th e large am ount of a present. The shrinkage of th e commercial alloys cannot be due entirely to decomposition of /8; it is highly probable th a t other phase changes occur which also cause shrinkage. The heat of decomposition of pure ft is 7-39 grm .-cal./grm . for th e 20% alum inium alloy and th e decomposition tem per
ature is ab o u t 277° C.—-A. R . P.
*An Analogy Between Plastic Deformation and Certain Cooling Rates in Causing “ Premature ” Precipitation in Supersaturated Solid Solutions. The Incubation Period.—I. J . L. B urns (Trans. Amer. Soc. Metals, 1934, 22, 728-736).—R eports a stu d y of th e age-hardening of D uralum in. The effect of rate of cooling on age-hardening and on th e incubation period was inves
tigated. I t was found th a t if a supersaturated solid solution is plastically deformed im m ediately after th e quenching operation, ageing begins earlier, there is no incubation period, and the final hardening due to precipitation is less. If a p articu lar rate of cooling is used in quenching from th e tem perature of m axim um solubility, ageing begins earlier, there is no incubation period, and th e final hardening will usually be less. From th is it is concluded th a t plastic deform ation does n o t increase th e rate of hardening, b u t m erely causes th e hardening to s ta rt earlier. P recipitation m ay tak e place during a cold- working operation or during quenching. W hen an incubation period ensues after quenching, it is suggested th a t the solute has been retained in its entirety during th e quenching operation. The hardness of quenched steel is prob
ably due to th e same cause as th a t of oil- or air-cooled D uralum in, nam ely, ageing during th e cooling operation. This analogy, if tru e, obviates any sharp°line of dem arcation between ferrous and non-ferrous alloys.—S. G.
f*The Present Status of Age-Hardening. R ichards H. H arrington (Trans.
Amer. Soc. Metals, 1934, 22, 505-524; discussion, 525-531).—The theoretical aspects of age-hardening are briefly outlined for 3 general ty p e s : (a) simple precipitation age-hardening, (b) simple lattice-strain age-hardening, and (c) complications due to allotropy. The practical significance of age-hardening alloys a t elevated tem peratures in relation to tensile stren g th an d for spring properties is discussed, an d a n interesting plan is given for exploring an unknown system . Cobalt added to age-hardening alloys acts in general fu rth e r to increase th e age-hardness an d often to increase th e tem perature of
1935
I I . — Properties o f Alloys 13
14 M etallurgical Abstracts
Vo l. 2m axim um age-hardness. I t m ay a c t generally in 2 ways : (1) as a “ desol
v en t,” reducing th e solubility of th e precipitating constituent, a t least p a rt of th e cobalt going into solid solution in th e solvent lattice ; (2) alm ost all of th e cobalt (if correctly added) enters into a te rn a ry co n stitu en t w ith th e precipitating agent, th u s usually decreasing th e solubility of th is precip itan t.
—S. G.
tAge-Hardening Alloys. --- (Metallurgist (Suppt. to Engineer), 1934, 10, 149-150).—A brief review of th e subject and a sum m ary of a p ap er by It. H . H arrin g to n (preceding ab stract).—R . G.
*Method of Radiation-Calorimetry for Determining the Thermal Conductivity of Metal Bars. P . V ernotte (Aérotechnique (Suppt. to Aéronautique), 1934, 12, 25).—A brief, illu strated note of a m ethod for determ ining th erm al con
ductivities by observing th e pow er dissipated b y a sm all electric furnace when a b ar of th e m etal is in serted in th e furnace in different positions. The con
d u ctiv ity of a brass b ar 50 mm. long an d 4 m m . in diam eter was found to be 0-29 cal./deg./cm ./sec.—J . C. C.
tAlloys [The Hume-Rothery Rules]. A non. (Metallurgist (Suppt. to Engineer), 1934, 10, 174-176).—A brief review of th e subjects of codification of d a ta relating to equilibria in alloy system s an d th e form ulation of rules on which to base reliable predictions. A paper by H um e-R othery, M abbott, a n d E vans (Met. Abs., 1934, 1, 296) is critically discussed. I t is pointed out th a t th e false valency factor or “ liquidus factor ” of H um e-R othery an d his collaborators, calculated from d a ta on copper an d silver alloys, is n o t a whole n um ber as claimed. In consequence, theoretical argum ents based on th is prem ise m ust be regarded as invalid, an d th e scientific basis of liquidus curves as n o t y e t know n. In th e prediction of th e freezing points of te rn a ry alloys, th e authors referred to have been singularly successful, an d though th e ir results are regarded as em pirical, th e line of investigation followed should provide a m easure by w hich experim ental results m ay be com pared and codified.—R . G.
Metallic Alloys. Anon. (W erkstatt u. Betrieb, 1934, 67, 353-354).—A sum m ary, giving th e average com position of a n um ber of alloys, classified as : copper alloys (not bronzes), bronzes, alum inium alloys, nickel alloys, zinc alloys, tin alloys, lead alloys, w hite (bearing) m etals, fusible alloys, light alloys, am algam s, silver an d gold alloys.—P . M. C. R .
A Metallurgical Survey of Engineering Material. Jo siah W. Jones (Met.
In d . (Lond.), 1934, 45, 537—541).—A n a b stra c t of th e “ non-ferrous ” portion of a p ap er dealing w ith both ferrous an d non-ferrous m etals, read before th e Birm ingham B ranch of th e In s titu tio n of P roduction Engineers. The strength to w eight ratio of heavy an d lig h t alloys, th e “ shapeability ” of alloys, th e th eo ry of hardening of D uralum in, th e hardening of copper alloys, p articu larly of K unial, perm anence as regards th e fractu re of defective m aterial an d th e w eakening of section due to corrosion, quenching non-ferrous alloys, and th e properties of heat-resisting alloys are discussed.—J . H . W.
III.— STRUCTURE
(M etallography; M acrography; C rystal S tru ctu re.)
Etching Polish for the Preparation of MetaUographic Samples. N. Zarubin, M. Suitm , an d N . Golikov (Zavadskaya Lab., 1933, (7), 49-53 ; C. A bs., 1934, 28, 7231). [In R ussian.] Osmond’s m ethod of polishing sam ples for m etallo- graphic analysis w ith an etching polish was used successfully n o t only for m etals such as tungsten, m olybdenum , ta n talu m , vanadium , &c., b u t for non- ferrous m etals an d alloys such as copper, alum inium , nickel, tin , lead, bronze,
&c. 16 references are given.—S. G.
1935
I I I . —Structure 15
*The Deformation Lines in Alpha Brass. Carl H . Samans (J. Inst. Metals, 1934, 55, 209-213).—A microscopic stu d y of 7 0 : 30 brass single crystals of 2 different orientations which had been reduced 50% in thickness by cold- rolling revealed th e presence of m any of th e so-called “ lines of deform ation.”
X -ray determ inations in th e rolling plane showed conclusively th a t th e m ark
ings were mechanical tw ins parallel to octahedral planes.—C. H . S.
♦An X-Ray Study of Orientation Changes in Cold-Rolled Single Crystals of Alpha Brass. Carl H. Samans (Metals Technology, 1934, (Oct.), A .I .M .M .E . Tech. Publ. No. 579, 1-15).—The lattice rotations found in rolled single crystals of 70 : 30 brass of 5 different initial orientations have been successfully explained on th e basis of plane parallelepipedal compression representation of th e forces of rolling. The active slip plane can be determ ined both from th e m axim um shear-stress law and th e m anner of rotation. One of 3 slip systems will be active according to th e rolling plane and direction of rolling chosen, and th e lattice rotations produced by deform ation will be a variation of one of th e following ideal positions of rolling plane and rolling d ire c tio n : (110), [112]; (110), [001]; (110), [ O il]; (001), [010]; (112), [111].— A. R. P.
♦Crystal Orientation in Drawn Brass Cups. L. H errm ann an d G. Sachs (Metallwirtschaft, 1934, 13, 745-752).—The degree of deform ation and the orientation of th e crystals a t various p a rts of a draw n 63 : 37 brass cup have been in v estig ated ; th e observed tex tu res correspond w ith those observed in simple deform ation processes, th u s where pure compression occurs th e corre
sponding fibre tex tu re is found w ith [110] as th e axis of th e films, and where elongation occurs a double-fibre te x tu re is formed w ith th e [111] and [200]
orientation. In th e o th er zones th e complex tex tu res formed correspond w ith th e complex n atu re of th e d eform ation; no tex tu re equivalent to th e rolling texture can be found in an y p a rt of th e draw n cup.—v. G.
♦Crystal Re-Orientation on Heating Drawn Copper Wires. G. S. F arn h am and H ugh O’N eill (J. In st. Metals, 1934, 55, 201-208).—The behaviour of a silver-free copper wire reduced 59% by cold-drawing, has been com pared after
“ low -tem perature tre a tm e n t (L.T.T.) w ith th a t of 2 silver-bearing wires reduced 59 an d 49% , respectively. L.T.T. hardening occurs in th e first, b u t not in th e second of these. X -ray spectroscopy m akes it evident th a t preferred orientation is less developed in these silver-bearing wires. The general effect of L.T.T. a t 130° C. is to reduce th e am ount of [111] preferm ent, b u t to cause an increase of [100] preferm ent. T his change-over probably causes “ orientation hardening.” I n these silver-bearing wires, however, th e change is only rela
tively sm all in ex ten t, an d th is appears to explain th e differences as regards L.T.T. hardening.—G. S. F .
♦An X-Ray Study of the Effect of Heat on the Structure of Sputtered Films of Gold. S. R am a Swamy (Proc. Phys. Soc. (Lond.), 1934, 46, 739-746).
Sputtered films of gold of different thicknesses were heated to various tem p era
tures up to 800° C. an d th e ir D ebye-Scherrer X -ray photographs determ ined a t each stage of heating. The photographs indicated th a t on being heated th e gold crystals in th e films oriented them selves so th a t th e ir 111 planes were parallel to th e surface of deposition. The crystals grew w hen th e films were heated. The degree of o rientation and size of crystals depended on th e thickness of film and on th e tem perature to w hich th e film was heated.—J . T.
♦The Crystal Structure of the Intermediate Phase Au2Pb. H arald P erlitz (Keemiateated, 1934, 2, (1), 1 1-16; Chem. Zentr., P )U , 105, I I , 2656-2657).—
The phase is cubic face-centred, a = 7'910 A., w ith 24 atom s in th e u n it cell.
The stru ctu re of th e cell is analogous to th a t of MgCu2 an d K B i2. A. R . P.
♦The Growth of Metal Crystals in Metal Vapours. III.[— Magnesium].
M. Straum anis (Z. physikal. Chem., 1934, [B], 2 6 ,246-254).—To te s t Kossel and S transki’s th eo ry of th e hom opolar grow th of crystals, experim ents have been made on th e sublim ation of m agnesium in hydrogen a t O'OOl—300 m m . pressure
