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

Lattice parameters for four Cu–Si alloys containing 2.2, 4.3, 6.4 and 8.7 at.% Si in the solid-solution range have been calculated in the temperature range 303–928 K. The lattice parameters increase slowly in a nonlinear manner with rise in temperature. The calculated linear thermal-expansion coefficients (α) at room temperature increase with increasing solute concentration (Si) but decrease almost linearly with increasing temperature, the rate of decrease being higher for alloys with higher solute concentration. All the alloys have almost the same average α value (α_av ~ 16.0 × 10⁻⁶ K⁻¹), which is the value of α at the temperature interval 615–625 K for all the alloy compositions.