Chapter 6: Thermal Properties
No description yet. This curated deck is ready for daily study.
Card preview (18)
refers to the response of a material to the application of heat. As a solid absorbs energy in the form of heat, its temperature rises and its dimensions increase.
thermal property
The energy may be transported to ___ of the specimen if temperature gradients exist, and ultimately, the specimen may melt.
cooler regions
properties that are often critical in the practical utilization of solids.
Heat capacity, thermal expansion, and thermal conductivity
is a property that is indicative of a material’s ability to absorb heat from the external surroundings; it represents the amount of energy required to produce a unit temperature rise
heat capacity
are in the form of lattice waves or phonons
atomic vibrations
Heat capacity… – increases with temperature – for solids it reaches a limiting value of 3R
Dependence of Heat Capacity on Temperature
Most solid materials expand upon heating and contract when cooled.
thermal expansion
dependence of fractional length change on the linear coefficient of thermal expansion and the temperature change
thermal expansion
3 Types of Thermal Expansion
• Linear expansion • Area expansion • Volume expansion
The relative expansion of the material divided by the change in temperature
coefficient of linear thermal expansion
is the phenomenon by which heat is transported from high- to low-temperature regions of a substance.
Thermal conduction
The property that characterizes the ability of a material to transfer heat is the
thermal conductivity
Atomic vibrations and free electrons in ___ regions transport energy to ___ regions
hotter, cooler
are stresses induced in a body as a result of changes in temperature. An understanding of the origins and nature of thermal stresses is important because these stresses can lead to fracture or undesirable plastic deformation.
thermal stresses
When a solid body is heated or cooled, the internal temperature distribution will depend on its ___ and ___, the thermal conductivity of the material, and the rate of temperature change.
size and shape
The capacity of a material to withstand failure (Crack formation and brittle fracture)
Thermal Shock of Brittle Materials
the resistance to thermal shock depends not only on the magnitude of the temperature change, but also on the ___ and ___ properties of the material
mechanical and thermal
The ___ is best for ceramics that have high fracture strengths σf and high thermal conductivities, as well as low moduli of elasticity and low coefficients of thermal expansion
thermal shock resistance