Key roles of particles in grain refinement and material strengthening for an aluminum matrix composite

Abstract An aluminum matrix composite (AMC) containing ~5% TiB2/TiC particles is processed by high-pressure torsion. The microstructures and mechanical properties of the composites are analyzed in detail. The processed AMC samples are compared to the corresponding monolithic matrix material to investigate the key roles of particles in grain refinement and material strengthening. It is found that a small portion of particles is beneficial for grain refinement while maintaining the integrity of the material. In addition, the presence of particles grants the ultrafine-grained AMC larger strain hardening capacity (energy storage capacity) than the ultrafine-grained aluminum.