1. Grain Boundaries Ni-Base Superalloy Waspalloy 50µm high-angle grain boundary (  >15°) low-angle grain boundary

2. Properties of Materials Mechanical Properties Elastic Plastic Viscoelastic Creep Testing methods

3. The Tensile Test stress  =F/A strain  =l-l 0 /l 0

4. The Tensile Test

5. Elastic Deformation distance r r0r0 Force=dE/dr

6. Elastic constants (isotropic case) Stress – strain / shear stress – shear strain Young’s modulus Shear modulus Poisson ratio In order to completely describe the elastic behavior of a solid 2 of these constants need to be known!

7. Yield Strength  Y 0.002 strain offset yield-point phenomenon (C steels, dislocations are pinned by C) YY YY

8. The Stress-Strain Curve stress strain necking engineering stress true stress

9. Materials Selection Charts Strength [MPa] Density [1000kg/m³]

10. Plastic Deformation – Dislocation Glide shear stress 

11. Plastic Deformation – Dislocation Glide =>macroscopic deformation

12. Plastic Deformation – Dislocation Glide dislocation motion

13. Plastic Deformation shear stress 

14. Some concluding words on dislocations Strengthening mechanisms Grain size reduction (Hall-Petch equation) Solid solution strengthening Strain hardening

15. Mechanical testing Hardness Vickers Rockwell … Nanoindentation Ductility Toughness Creep Fatigue

16. Vickers Microhardness Testing length of the diagonals d 1 and d 2

17. Rockwell Hardness Testing (HRC) scale indenter (120° diamond pyramid) specimen

18. Ductility stress strain %EL, percent elongation %RA, percent reduction in area brittle ductile

19. Charpy Impact Testing hammer impact energy A v =mg(h-h´) specific a k =A v /A 0 (DIN 50115)

20. T-Dependence of Av BDTT

21. Cleavage Fracture at Low Temperatures

22. Deformation at Elevated Temperatures: Creep 

23. Creep Testing d  dt

24. Fatigue Loading during Service

25. Fatigue Testing

26. push-pull rotating-bending counter load servohydraulic actuator

27. Fatigue-Testing: The S/N Diagram stress amplitude [MPa] cycles to failure N fatigue limit total life design

28. Fracture Mechanics K Ic represents resistance to brittle fracture [MPam 0.5 ]

29. Determination of K Ic using Compact Tension (CT specimens) extensometer force displacement