What are the major mechanisms of solid state diffusion?

1. What are the major mechanisms of solid state diffusion?
2. What is carburizing process? Its purposes? What is decarburizing?
3. What is case hardening?
4. What is the major driving force for atomic diffusion?
5. What is diffusion flux? How is it calculated?
6. What is steady-state diffusion? Fick’s first law?
7. What is non steady-state diffusion? Fick’s 2nd law?
8. Do you know how to calculate the diffusivity (diffusion coefficient)?
9. Do you know how to use the solution to Fick’s 2nd law for surface diffusion?
10. Do you know how to properly use the Gaussian error function table? Find inverse error function value?
11. What is true stress? True strain?
12. How are engineering stress, engineering strain, true stress, and true strain related?
13. Name three elastic moduli. How are they related?
14. What is Poisson’s ratio?
15. What mechanical properties can be determined from tensile test? How are they determined?
16. What is elastic deformation? Plastic deformation?
17. What is the physical significance of proportional limit?
18. What is mechanical necking in tensile deformation? What causes the necking?
19. What is the physical meaning of modulus of resilience?

20. What is a slip system?
21. Do you know how to calculate resolved shear stress for a slip system?
22. What’s Schmid’s factor? What’s the maximum possible value of the factor?
23. Can you describe common strengthening methods for metals?
24. What are the stages in property and grain structure changes during heat treatment of cold-worked
metal? Do you know how properties change in these stages?
25. What are the differences between ductile fracture and brittle fracture?
26. What is stress concentration? What is theoretical stress concentration factor?
27. How is the impact toughness of a material determined?
28. How is the ductile-to-brittle transition temperature determined?
29. What’s mechanical fatigue of materials?
30. What is S-N curve? How is it determined?
31. What is endurance limit (fatigue limit)? What is fatigue strength?
32. What are the main factors that have influence on the impact toughness of metals?

33. What are the possible modes of crack propagation? What are the differences between them? Which
is most effective mode?

34. How are stress amplitude, mean stress, stress range, and stress ratio of cyclic stresses calculated?
35. What is Paris Equation?

36. 17. Do you know how to use the fracture toughness equation for failure analysis and material
selection in design? What’s y in the equation? What controls the value of y?
37. What’s creep of material? What are the stages? What is creep rate?

38. What major factors have effects on the creep rate?

39. What’s Larsen-Miller parameter? How can it be used to analyze creep failure?
40. What is Gibbs phase rule? Do you know how to use it?
41. You should know how to read and use phase diagrams.
42. Given alloy composition and temperature, you should know how to determine (a) phases present in
the material, (b) composition of each phase, and (c) amount or weight fraction of each phase.

43. Can you identify invariant points and associated reactions on cooling (or heating)?

44. Can you write the reaction of eutectic and eutectoid reactions?

45. Why do eutectic and eutectoid transformations produce layered microstructure?
46. Do you know important phases such as austenite, ferrite, and cementite in steel?
47. How is pearlite made?
48. What is the carbon concentration in the cementite (iron carbide)?
49. How much do you about pearlite, bainite, and martensite? How are they made?