Microstructure and composition segregation along the fluidity length of aluminum alloy in squeeze casting

This study investigated the spiral line sample of A357 prepared by the squeeze casting (liquid die forging) process and the influence of the fluidity length on the composition segregation and microstructure segregation through chemical composition and metallographic analyses. The results show that the Si and Mg mass fractions of the start and the end of the spiral line sample along the flow length are greater than that in the middle of the spiral line sample. The initial grain size of α first increases, then decreases with the increase of the fluidity length. Meanwhile, the phase rate of the primary solid shows a fluctuating change with the increase of the fluidity length. The composition segregation and the microstructure change are caused by the forced flow of the filling liquid in the squeeze casting process.