Abstract:The 2024Al/Gr/SiC hybrid composite plates with 5%-10% SiC particles (volume fraction) and 3%-6% flaky graphite (Gr) (volume fraction) were fabricated by vacuum hot pressing and hot extrusion processing. The effects of SiC and Gr on the microstructures and mechanical properties of the composites aged at 160, 175 and 190 °C were studied by optical microscopy, scanning electron microscopy (SEM), and hardness and tensile tests. The results indicate that the SiC particles have a more obvious effect on accelerating the aging response as compared with the Gr. Both the tensile strength and elongation are reduced by the Gr and SiC particles added into the matrix, while the Gr has a more negative influence on the elongation than the SiC particles. The tensile strength (σ_b), yield stress (σ_s) and elongation (δ) of the 2024Al/3Gr/10SiC composite aged at 165 °C for 8 h are 387 MPa, 280.3 MPa and 5.7%, respectively. The hybrid composites are characterized by ductile fracture, which is associated with the ductile fracture of the matrix and the tearing of the interface between the matrix and the particles.

Key words: 2024Al/Gr/SiC composites; vacuum hot pressing; microstructure; mechanical property; heat treatment