Chapter 7

Question 1

bi-axial tension

Answer 1

stress > 0

Question 2

hydrostatic compression

Answer 2

stress < 0

Question 3

Brittle fracture means small toughness. (T or F)

Answer 3

True

Question 4

tensile strength

Answer 4

maximum stress on stress-strain curve

Question 5

For plastics, the maximum on a stress-strain curve appear on the necking. (T or F)

Answer 5

False, for metals

Question 6

modulus of elasticity

Answer 6

stiffness of a material (slope)

Question 7

Elastic deformation is nonpermanent and reversible. (T or F)

Answer 7

True

Question 8

What do strongly bonded interatomic forces led to?

Answer 8

A larger modulus of elasticity (E)

Question 9

Plastic deformation is nonpermanent and reversible. (T or F)

Answer 9

False, permanent and nonrecoverable

Question 10

yield strength

Answer 10

stress at which noticeable plastic deformation has occurred

Question 11

ductility

Answer 11

amount of plastic deformation at failure

Question 12

resilience

Answer 12

ability of a material to absorb energy during elastic deformation

Question 13

toughness

Answer 13

amount of energy absorbed before fracture (area under curve)

Question 14

Ceramic materials are more brittle than metals. (T or F)

Answer 14

True

Question 15

Elastic deformation is displayed as linear on stress-strain graph. (T or F)

Answer 15

True

Question 16

Plastic deformation is displayed as linear on stress-strain graph. (T or F)

Answer 16

False, nonlinear

Question 17

hardness

Answer 17

measure of resistance to surface plastic deformation

Question 18

Large hardness (2)

Answer 18

1. high resistance to deformation from compressive loads
2. better wear properties