Ch. 19 Thermal Properties

Question 1

Effects of T on metal

Answer 1

Higher volume, less conductivity

Question 2

Effects of T on ceramics

Answer 2

Thermal shock susceptible, thermal insulators

Question 3

Effects of T on polymers

Answer 3

Soften(thermoplastics), thermal insulation

Question 4

Heat capacity quantitative definition

Answer 4

Energy required to raise T of material

Question 5

Heat capacity equation (not valid with phase transformation)

Answer 5

C = dQ / dt

Question 6

Two ways to measure heat capacity

Answer 6

Constant pressure, Constant volume

Question 7

C unit of measurement

Answer 7

Phonons(from phono = sound)

Question 8

Heat capacity to T graph

Answer 8

Is directly proportional, reaches a limiting value of 3R (gas constant)

Question 9

Heat capacity of materials (from least to most )

Answer 9

Metals, Ceramics, Polymers

Question 10

Thermal Expansion formula

Answer 10

delta l / l0 = strain = a1(coefficient of thermal expansion) * delta T

Question 11

Thermal expansion is caused by

Answer 11

Assimetric energy - Distance curve of interatomic distances

Question 12

Thermal coefficient expansion of material (from least to most)

Answer 12

Metals, Ceramics, Polymers

Question 13

Bimetal thermostats

Answer 13

Work with two metals with different a1s

Question 14

Fouriers law - Thermal conductivity

Answer 14

q (thermal flux) = -k (thermal conducitivity) * dT / dx

Question 15

k (thermal conductivity) of materials from least to most

Answer 15

Polymer, ceramics, metals

Question 16

Are alloys good for conductivity?

Answer 16

NO

Question 17

Thermal stresses occur due to

Answer 17

Restrained thermal expansion/contraction & temperature gradients ( uneven heating / cooling)

Question 18

Thermal stress formula

Answer 18

σth = E * a1 * (deltaT) = E * Strain thermal

Question 19

Quench rate formula

Answer 19

delta T= Quench rate / k

Question 20

Thermal shock resistance formula

Answer 20

delta T frac = σf / E * al