An X-ray determination of the thermal expansion of α-phase Cu–Al alloys at high temperature

The lattice expansion of four Cu–Al alloys in the solid-solution range containing 3.7, 6.7, 12.3 and 18.4 at.% Al have been determined by X-ray diffraction in the temperature range 303–923 K using a Unicam 19 cm high-temperature powder camera. In all cases the measured lattice. parameters have been found to increase non-linearly with increasing temperature, from which the linear thermal expansion coefficients (α) have been determined. The α values have been found to decrease with increasing temperature; but the average α values increase slowly with the increase of Al concentration.