Download presentation

Presentation is loading. Please wait.

Published byNehemiah Burdsall Modified over 2 years ago

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) YY YY

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

Similar presentations

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google