High temperature deformation behavior and optimal hot processing parameters of Al-Si eutectic alloy

摘要

High temperature deformation behavior of Al-Si eutectic alloy was investigated by compression tests conducted at various temperatures (563, 603, 643, 683, 723, and 763 K) with various strain rates of 0.001, 0.01, 0.05 and 1 s~(-1). Hot processing map and extrusion test were used to optimize hot processing parameters. The results that are obtained show that the main high temperature deformation mechanism of the Al-Si eutectic alloy is dislocation movement. The difference between the maximum deformation activation energy of 178 kJ/mol and self-diffusion activation energy of pure aluminum results from rupture of eutectic silicon crystals. The deformation activation energy and instable domain decrease with increasing strain. Then the effects of strain on deformation activation energy and instable domain are negligible at higher stain than 0.4. The optimal hot processing parameters of the Al-Si eutectic allFoy are deformation temperature ranging from 660 K to 723 K, lower strain rate than 10~(-1.5) s~(-1) and strain of 0.51-1.20.