Heat Treatment Strengthening for TiB₂/AlSi7Mg0.6 Composite

TiB2 particles reinforced AlSi7Mg0.6 alloy (TiB2/AlSi7Mg0.6) composite was prepared by in-situ synthesis method through salt-metal reaction of K2TiF6 and KBF4 salts with the molten alloy. The composite was solution treated and aged. The microstructure and property of the composite after strengthening heat treatment were investigated by optical microscopy (OM), transmission electron microscopy (TEM) and hardness test. The results show that particles of TiB2 significantly refine the microstructure of the matrix alloy. After solution treatment the aging time to achieve hardness peak for the composite material was shorter than that of the AlSi7Mg0.6 matrix alloy, and the peak hardness increase degree of the composite was smaller than that of the matrix alloy, which was attributable to the insufficient precipitation of strengthening phase because of the fine grain size and large grain boundary area of aluminum matrix.