CH 6 - Mechanical Properties Flashcards
1
Q
What is elastic deformation?
A
reversible damage
2
Q
What is plastic deformation?
A
permanent damage
3
Q
What is yield strength?
A
stress at which noticeable plastic deformation has occurred
4
Q
What is tensile strength?
A
- max stress on engineering stress-strain curve
- for metals, occurs when noticeable necking starts
- for polymers, occurs when polymer backbone chains are aligned and about to break
5
Q
What is ductility?
A
plastic tensile strain at failure
6
Q
What is toughness?
A
- energy to break a unit volume of material
- approximate by the area under the stress-strain curve
7
Q
What is resilience?
A
- ability of a material to store energy
- energy stored best in elastic region
8
Q
What is hardness?
A
- resistance to permanently indenting the surface of a material
- large hardness = resistance to plastic deformation or cracking in compression & better wear properties
