Mechanical Properties
- Stress = force / area; Strain = change in length / original length.
- Elastic (Young's) modulus = stress / strain in the elastic region → stiffness (higher = stiffer).
- Resilience = energy absorbed up to the elastic limit (area under the elastic part of the curve).
- Toughness = total energy to fracture (area under the whole stress–strain curve).
- Hardness tests: Knoop and Vickers (microhardness), Brinell and Rockwell (macrohardness).
Other Terms
Yield strength, ultimate tensile strength, ductility/malleability, and creep are also tested. Brittle materials (ceramics) have low strain to fracture.
Exam Tips ⭐
Modulus = stiffness; resilience = elastic energy; toughness = total energy to fracture; Knoop/Vickers = microhardness.