Lattice thermal conductivity of deformed and annealed aluminum alloys in the temperature range 1.3-60 K

Abstract

The thermal conductivity of several aluminum-magnesium and other aluminum alloys has been measured between 1.3 and 60 K in order to study point defects and dislocations in these metals. The measured thermal conductivity is separated into electronic and lattice components. The lattice thermal conductivity of each sample is analyzed in terms of the scattering of phonons by electrons, dislocations, and point defects. The measured lattice thermal conductivity of the well-annealed specimens at 10 K is in good agreement with a theoretical estimate of the effect of phonon scattering by electrons. Samples deformed by swaging have a larger lattice thermal resistivity which is shown to be due to dislocations in concentrations as large as 2 × ${10}^{11}$ ${\mathrm{cm}}^{-2\mathrm{}}$ in the heavily deformed samples. The dislocation densities deduced from the lattice thermal conductivities are compared to estimates from electron microscopy. The rate of phonon scattering by point defects is shown to scale with magnesium concentrations in the aluminum-magnesium alloys; its magnitude is consistent with the local lattice distortion that accompanies the introduction of a magnesium atom into the aluminum lattice.