Microstructural characterisation of novel 6351 Al–Al₄SiC₄in-situ composite

Abstract

6351 Al–Al4SiC4 composite has been developed through stir casting route by incorporation of fine TiC powder in 6351 Al melt. Simultaneous effects of the generation of in-situ particles (Al4SiC4 and Al3Ti) and grain refinement were observed. The in-situ generated Al4SiC4 particles were found to act as nucleation sites for primary α (causing grain refinement) along with engulfment effect promoting uniform particle distribution. As the volume fraction of Al4SiC4 particles increased, the dendritic solidification was suppressed (more equiaxed grains appeared) and overall grain size of the matrix decreased. Besides, the precipitation of Al3Ti occurred at the dislocation enriched region. Accordingly, hardness of the composite was improved with increasing content of Al4SiC4 particles.