Core–shell structured al-matrix composite with enhanced mechanical properties

Abstract

Al-matrix composites with different contents of core–shell structured B4Cp–Cu reinforcement were prepared by electrolessly coating Cu on B4Cp and hot sintering the mixture of B4Cp–Cu and Al powder. The influences of solution treatment on the microstructure and mechanical properties were investigated. The results showed that the initial Cu shell was changed into Al2Cu shell, and part of Cu was dissolved into the Al matrix after solution treatment at 540°C. With increasing solution dwelled time, the yield strength, ultimate compressive strength and ductility were improved gradually. As compared with the pure B4Cp reinforcement, the introduction of core–shell structured B4Cp-Cu and subsequent solution treatment improved the mechanical properties of Al-matrix composite. The improvement of mechanical properties is attributed to the fact that the Al2Cu shell moderates the modulus mismatch and enhances the interface bonding between Al and B4Cp, and that heat treatment introduces solution strengthening of Cu element into the Al matrix.