Effect of Intensification Pressure on Eutectic Si Segregation of Al-12Si-1Cu Alloy in Squeeze Casting

Abstract

Squeeze casting is an advanced technology to produce aluminum alloy components with excellent mechanical property. Due to good fluidity and castability, the Al-Si alloy is the most common aluminum material in squeeze casting. However, the segregation in solid α-Al phase and liquid eutectic Si phase happens during solidification, which leads to microstructural inhomogeneous in the final microstructure. In this study, the eutectic Si segregation of Al-12Si-1Cu alloy under different intensification pressure in squeeze casting was investigated by Optical Microscopy (OM). The results show that increasing intensification pressure promotes the eutectic Si segregation at center zone, while the eutectic Si phase at skin zone is not much influenced. Increasing the intensification pressure from 65 MPa to 140 MPa, the segregation degree of eutectic Si at center zone increases from 0.05 to 0.29, while the segregation degree at skin zone levels at 0.2. Under high intensification pressure, the feeding effect of liquid phase at center zone is prominent, which results to high tendency of eutectic Si segregation in the final microstructure.