The work to which we have set ourselves is the liberation of the imagination, and the harnessing of the imagination to man’s physical creativity - Friedre Ginaz
Hardness Resistance to indentation
Hardness Resistance to indentation Greater hardness gives higher hardness nos.
Types of hardness tests
Comparison of hardness scales
Example - quenched plain carbon steels
Correlation betwn strength & hardness Harder means stronger for metals & alloys
Toughness Resistance to being clobbered
Toughness Resistance to being clobbered Impact test measures energy absorbed upon fracture measure of toughness
Toughness Resistance to being clobbered
Impact test measure impact energy at different temperatures
Impact test measure impact energy at different temperatures
Impact test measure impact energy at different temperatures
Fracture toughness - KIc = Yc 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
Creep deformation under small loads at elevated temps.
Fatigue deformation under small cyclic loads
Fatigue S-N curves & endurance limit
Assignments for next class: 1. review today's classnotes; know hardness tests; impact test & temperature effect: 3 stages of creep; S-N curves 2. Read text: pp. 201-203, sections 8.6-8.8, pp 221-225