Effect of SIMA Process on Microstructure and Wear Behavior of Al-Mg₂Si-3% Ni Composite

The microstructural evolution and wear behavior of Al-Mg₂Si-3% Ni in situ composite during strain-induced melt-activated (SIMA) process were investigated in this study. In order to induce strain in samples, they were cold deformed by the compression ratio of 10% reduction. Then, they were isothermally re-heated at 540 °C for 20, 40 and 60 min. It was observed some cracks in primary Mg₂Si particles which lead to reduce the size of these particles and distribute more uniformly in matrix. Also, they became more globular after SIMA process. Furthermore, the brittle network of eutectic phase has altered remarkably during this process from flake-like to rod- or dot-like. The wear resistance of specimens improved remarkably after SIMA process. It was found that this improvement can attribute to microstructural changes, especially eutectic Mg₂Si phase, because this microstructure can curb the crack nucleation in delamination mechanism and consequently reduces the wear rate.