1. Hardness
Resistance to indentation

2. Hardness
Resistance to indentation
Greater hardness
gives higher
hardness nos.

3. Types of hardness tests

4. Comparison of hardness scales

5. Example - quenched plain carbon steels

6. Correlation betwn strength & hardness
Harder means stronger for metals & alloys

7. Toughness
Resistance to being clobbered

8. Toughness
Resistance to being clobbered
Impact test measures energy absorbed upon fracture
measure of toughness

9. Toughness
Resistance to being clobbered

10. Impact test
measure impact energy at different
temperatures

11. Impact test
measure impact energy at different
temperatures

12. Impact test
measure impact energy at different
temperatures

13. Fracture toughness - Kic = Yc a
resistance to brittle fracture in presence of a
crack - resistance to crack propagation under
load
common specimen configuration
usually pre-cracked here before testing

14. Creep
deformation under small loads at elevated temps.