On the age hardening behavior of thixoformed A356-5TiB_2 in-situ composite

摘要

The present article investigates the age hardening behavior of thixoformed A356-5TiB_2 in-situ composite prepared by a salt-metal reaction. The non-dendritic feedstock for thixoforming was prepared by a cooling slope casting technique. The results show that the thixoformed A356-5TiB_2 composite attains the peak hardness in only four hours. The detailed microstructural analysis of thixoformed composite shows that enhanced ageing can be attributed to high dislocation density generated in α-Al matrix due to thermal mismatch and the thixoforming process itself. Furthermore, it was found that thixoforming not only increases the tensile strength of thixoformed composite in peak-aged condition but also increases the ductility by ～7.4%.