Heat transfer thermoelasticity

In addition to the temperature dependence of the properties such as strength and modulus, which we will discuss individually for each material class, there are two fundamental topics that are often described in the context of heat transfer properties or thermodynamics of materials—for example, thermal conductivity or specific heat—but are related more to mechanical properties because they involve dimensional changes. These two properties, thermoelasticity and thermal expansion, are closely related, but will be described separately. 

In our own recent low temperature studies45 of ultra high drawn polyethylene, a change in the background level of tan 6 in tensile tests when the environmental gas is changed, is attributed to thermoelastic effects resulting from the different heat transfer characteristics of the gases used. 

Several issues must be addressed. First, the heat-transfer environment must yield a well-controlled temperature field in the crystal and melt near the melt-crystal interface so that the crystallization rate, the shape of the solidification interface, and the thermoelastic stresses in the crystal can be controlled. Low dislocation and defect densities occur when the temperature gradients in the crystal are low. This point will become an underlying theme of this chapter and has manifestations in the analysis of many of the transport processes described here. 

Bertman B and Sandiford DJ 1970 Second sound in solid helium. Sci. Am., 222(5), pp. 92-101. Chandrasekharaiah DS 1986 Thermoelasticity with second sound ar vi w.Appl. Mech. l ev.,39,p. 355. Flik MI, Choi BI, and Goodson KE 1992 Heat transfer regimes in microstructures. / Heat Transfer, 114, pp. 666-674. 

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