Strengthening effects of Mg-Si precipitates on wear resistance of SiCp/Al-Si-Mg composites

Abstract

The effects of Mg on wear resistance of SiC_p/Al-Si-Mg composites were studied. Comparative analyses between equivalent von-Mises stresses and yield stresses of α-Al and SiC were calculated, and quasi-in-situ observation were conducted to reveal the wear behavior and modes. During reciprocating frictions, the matrix with better plasticity is the weak part in composites. Due to the deformation discontinuity, the interface between SiC and matrix tends to separate leading to surface cracks and wear failure. Therefore, increasing the strength of α-Al and improving the deformation coordination between α-Al and SiC are the crux to improve wear resistance. 1 wt% Mg addition introduces Mg-Si GP zones and B′ precipitates into α-Al, resulting in precipitation strengthening which improves the wear resistance of composites.