The effect of plastic deformation on the thermal conductivity of copper alloys

• Main Author: Leaver, Anthony D. W.
• Published: University of Surrey 1969
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.751743

The thermal conductivity of a specimen of alpha-brass has been measured and the dislocation-phonon scattering power, sigma, deduced. The dislocation density was determined by transmission electron microscopy. By comparison with similar measurements made on copper-aluminium alloys (Salter, 1965), it has been shown that sigma depends on the type and concentration of solute element and not upon the dislocation arrangement. A theory to account for the variation in sigma (Klemens, 1968) , has been critically considered. For annealed specimens at liquid helium temperatures the lattice thermal conductivity, limited by electron-phonon scattering, has a quadratic temperature dependence. However, for deformed specimens deviations from a pure T[2] dependence were found and have been attributed to the scattering of phonons by dipole dislocations. Measurements have been made of the thermal conductivity of specimens of Cu+2at.%Al, Cu+12at.%Al, and Cu+10at.%Au after successive amounts of tensile deformation. The value of sigma for the latter alloy has been deduced. The results are used to provide information on the mechanism of work hardening in these materials. It is shown that the important parameter is the relative atomic size of solute and solvent and not the electron concentration. Measurements of the residual electrical resistivity of the specimens yield information on the variation in stacking fault widths with deformation.