Study on the Precipitation Behavior of SiC/7075Al Composite Material Controlled by Pulse Current-Assisted Treatment

Abstract

In order to further improve the comprehensive mechanical properties of as-rolled SiC/7075Al composites, the microstructure and mechanical properties of the composites are modified by pulse current-assisted treatment (PCAT). The results show that the pulse current acts on the interior of the material in a unique way, reducing the nucleation barrier of the precipitated phase. Two nano-scale precipitated phases of MgZn₂ (η′) and Mg₂Si (β′) are formed inside the composite. The fine precipitates play a significant role in the strengthening of dislocation and dispersion of the material, which makes the material obtain excellent strength and plasticity. The mechanical properties analysis reveals that the yield strength (YS), ultimate tensile strength (UTS), and elongation of the samples subjected to PCAT are 223.6, 434.5 MPa, and 20.6%, respectively. Compared to the as-rolled samples, the YS exhibits an enhancement of 4.7%, the UTS increases significantly by 25.6%, and the elongation improves remarkably by 108%. PCAT enhances the strength and plasticity of SiC/7075Al composites, breaking the competition between strength and plasticity.