Hot tearing susceptibility of TiB 2 -reinforced Al–5Cu matrix composite

This work investigated the hot tearing susceptibility of TiB₂ reinforced Al–5Cu matrix composites. The results indicated that the hot tearing susceptibility of Al–5Cu alloy was significantly decreased when the TiB₂ content was less than 3%. The improvement was attributed to the TiB₂ particles promoted the grain refinement. The hot tearing susceptibility of TiB₂-reinforced Al–5Cu matrix composite decreased first and then increased with the increase of TiB₂ content. The 2TiB₂/Al–5Cu composite had the smallest hot tearing susceptibility value. It could be ascribed to the refined grain and shortened solidification temperature range, which contributed to the hot tearing susceptibility decrease. Nevertheless, the 4TiB₂/Al–5Cu and 6TiB₂/Al–5Cu composites had more severe hot tearing susceptibility than others. The reason was that the enlarged solidification temperature range increased the solidification shrinkage strain, which was adverse to the hot tearing susceptibility improvement. Furthermore, the increase of TiB₂ led to the formation of large particles agglomeration, which lowered the hot tearing initiation force and the feeding capacity of liquid metal.