Microstructural homogeneity, mechanical properties, and wear behavior of in situ Mg2Si particles reinforced Al–matrix composites fabricated by hot rolling

In situ Mg2Si particles often show coarse and irregular morphologies in Al–matrix composites, which results in inhomogeneous microstructures and poor mechanical properties. This leads to poor deformation ability in Mg2Si particles reinforced Al–matrix composites. Herein, a refined process exploiting refined Mg2Si particles was developed to enhance microstructure homogeneity after hot rolling in an Al-11.73%Mg-6.63%Si composite. The hot-rolled sheet reduces the macroscopic cracking on the edge when the Mg2Si particles of the as-cast microstructure are refined by the addition of phosphorus. The refined Mg2Si particles in the as-cast state shows further size reduction and exhibits homogeneous distribution by hot rolling (reduction of 76%). The microstructure also shows uniform deformation zones, subgrains and high-density dislocation regions via hot rolling. The homogeneous deformation microstructure results in needle-like, high-density precipitates after artificial aging and decreases the stress concentration of load bearing, which is beneficial to the tensile properties and wear resistance of the composite. The wear behavior of the composites improves with Mg2Si-particle refinement and microstructural homogeneity.