Index of /rozprawy2/11252

3 Table of contents

I. INTRODUCTION ... 5

II. LITERATURE REVIEW ... 6

1. Characteristics of Inconel 718 superalloy ... 6

2. Alloy chemical elements and their microstructural effects ... 7

3. Constituent phases of Inconel 718 superalloy ... 8

3. 1. γ phase ... 8

3. 2. γ’ phase ... 9

3. 3. γ’’ phase ... 10

3.4. Specific morphology of γ’ and γ” precipitates: co-precipitates and precipitates with a compact morphology ... 13

3.5. Transformation: γ’’  δ phase and γ‘  η phase ... 17

3.6. Carbides ... 18

3.7. TCP phases ... 19

4. Properties of Inconel 718 superalloy required for various applications ... 23

5. Processing and heat treatment of Inconel 718 ... 29

6. Heat treatment ... 30

7. Homogenizing treatment ... 33

8. Mechanisms of Inconel 718 superalloy strengthening ... 34

9. Creep resistance of Inconel 718 ... 39

10. Modeling and simulations of IN718 superalloy microstructure ... 42

III. Aim of investigation ... 45

IV. Experimental details ... 46

1. Material for investigation ... 46

2. Scope of the research (investigation) ... 48

2.1. Light microscopy (LM) ... 48

2.2. Scanning electron microscopy (SEM) and FIB-SEM tomography ... 48

2.3. Transmission- and scanning transmission electron microscopy (TEM and STEM) . 48 2.4. Image analyses ... 51

2.5. Electron tomography ... 53

a) EFTEM tomography ... 53

b) FIB-SEM tomography ... 53

3. Specimens preparation for microstructure investigation ... 54

3.1. Light - and scanning electron microscopy (LM, SEM)... 54

3.2. Transmission electron microscopy (TEM) ... 55

4 1. Quantitative microstructural analyses by light microscopy and scanning electron

microscopy ... 55

2. Analyses of the chemical composition by SEM/EDX spectrometry ... 74

3. Microstructure of Inconel 718 analyzed by transmission electron microscopy ... 75

4. Quantitative analyses of γ' and γ'' particles by tomography methods ... 77

4.1. Electron tomography ... 77

4.2. FIB-SEM tomography ... 81

5. Chemical elemental maps obtained by STEM-EDX ... 86

6. Effect of microstructure evolution on IN718 mechanical properties ... 97

VI. DISCUSSION ... 102

VII. CONCLUSIONS ... 105

LITERATURE ... 107

LIST OF SYMBOLS AND ACRONYMS ... 116

Acknowledgements ... 118

Appendix: ... 119

1) ChemiSTEM™ technology ... 119