Synergistic strengthening of copper matrix composites with carbides of different aspect ratios

Abstract

Copper matrix composites, known for their high strength, derive their desirable mechanical properties from strengthening effects of reinforcement. However, a single reinforcement provides a limitation of improvement in strength at the expense of plasticity. A strategy of synergistic improvement of strength and plasticity has been developed by incorporating two reinforcements with different aspect ratios. To this end, WC nanoparticles and SiC whiskers-reinforced copper matrix composites (WC_p-SiC_w/Cu) were prepared by intermittent pulsed electrodeposition and spark plasma sintering. These composites are designed with a unique core-shell structure, and thereby the agglomeration of reinforcements can be effectively avoided during sintering. As a result, the yield strength (323 MPa) of the WC_p-SiC_w/Cu is about double that of pure copper, while maintaining a high uniform elongation (15.3 %). The synergistic strengthening of the composites arises from the complementary advantages of the SiC_w(s) and WC_p(s). The results provide a promising route to preparing composites with comprehensive mechanical properties.