Research on Characteristics of Heat Treatment of Squeeze Cast Al-Cu-Mg Alloy

Abstract

A high strength Al-Cu-Mg alloy was prepared by squeeze casting. The effects of squeeze casting and heat treatment on the microstructures and mechanical properties of the alloy were studied. It was found that squeeze casting refined the microstructure and reduced the micro-segregation markedly, and also accelerated the diffusion process of solute atoms during solution heat treatment. Tensile strength and elongation of squeeze casting alloy were much higher than those of gravity casting alloy under both the as-cast and heat-treated conditions. In addition, the Al-Cu-Mg alloy prepared by squeeze casting showed good natural aging response, and the naturally-aged alloy possessed a slightly lower tensile strength but better elongation compared to full artificial aging. After solution heat treatment at 495 for 9h and further natural aging for 48h or artificial aging at 190 for 6h, the tensile strength of squeeze casting alloy reached to 472MPa and 475MPa, respectively, and the elongation was 18.9% and 12.7% accordingly. Based on the experimental results, the mechanism of microstructural evolution of squeeze casting Al-Cu-Mg alloy during heat treatment was discussed, and the effect of squeeze casting on the kinetics of solute diffusion and aging precipitation was studied.