CHAPTER 6 Flashcards
What does the straight line slope on stress strain curve show?
Young’s modulus
What are the types of deformations?
Elastic - nonpermanent and reversible
Plastic - permanent and irreversible
What is the elastic modulus proportionate to?
Slope of interatomic bonding force (dF/dr)_r0
What are isotropic materials?
Materials whose properties remain the same when tested in different directions
On a molecule level, what happens during a plastic deformation?
Bonds stretch and atoms displace and stay displaced
Planes slide
What is tensile strength
Maximum stress on engineering stress-strain curve
When does tensile strength occur for metals?
At the onset of noticeable necking
How does the slope of stress-strain curve relate to ductility?
Greater slope = LOW ductility
What is the resilience of a material?
Ability of a material to absorb energy during elastic deformation
What is toughness of a material?
Amount of energy of energy absorbed before fracture
How do you find the toughness of the material?
Approximate it by finding the area under the stress-strain curve before fracture
Which are more tough, rubber or glass?
RUBBER
What is hardness of a material?
Measure of resistance to surface plastic deformation—dent or scratch
