Proportional/Elastic limit - Answers Stress and strain values at the end of the linear elastic
region (straight part on curve)
Yield Strength - Answers Stress at plastic strain offset of 0.002
Tensile strength - Answers Maximum stress of the engineering curve (Maximum point on graph)
(where necking starts to appear)
Ductility - Answers Measure for deformation of the plastic (end point on the curve)
Resistance to fracture - Answers High to low
1. Metals
2. Composites
3. Ceramics
4. Polymers
Elastic: Resilience - Answers what energy can be stored
Elastic and plastic: Toughness - Answers what energy can be stored in elastic and plastic
True stress - Answers force/current area
True strain - Answers natural log of L sub i over L sub o
Hardness - Answers • Resistance to localized plastic deformation
• Resistance to denting, scratching, abrasion, cutting
• Resistance to permanent deformation when load is applied
Vickers Micro indentation - Answers • Small loads applied to micrometer sized areas provide a
measure of non - homogeneity
• A well-polished surface is needed for accurate measurement
• HRC- diamond cone
• HRB - 1/16" diameter steel ball
Crystalline materials - Answers atoms pack in periodic 3D repewated arrays in long range order
Non-Crystalline materials - Answers no long range periodic packing, some sort of range order,
amorphous