The effects of cooling rate and heat treatment on mechanical and thermal characteristics of Al-Si-Cu-Mg foundry alloys

The microstructure of the Al-9.7Si-0.7Cu-0.4Mg alloy solidified by different cooling rates was reported in this study and solution heat treatment followed by aging treatment was carried out for the effects of heat treatment on mechanical and thermal characteristics. The solution treatment was performed at 535 degrees C for 6 h and then the specimens were cooled by water quenching. The samples were aged at 180 degrees C or 190 degrees C for 1-10 h. By heat treatment, the long needles of eutectic silicon particles were broken down into smaller fragments and then gradually spheroidized. Spheroidizing of the eutectic silicon particles has found to improve the tensile strength and thermal diffusivity of the alloy. In particular, as increasing the aging temperature of Al-Si-Cu-Mg alloy from 180 degrees C to 190 degrees C, the 3% higher thermal conductivity was achieved. (C) 2014 Elsevier B.V. All rights reserved.