Improving mechanical properties of Cu/Ti3AlC2 composites via in-situ decomposed gradient interfaces

Ti3AlC2 is a promising reinforcement for Cu matrix composites. In this paper, the Cu/20 wt%Ti3AlC2 composites were fabricated using a spark plasma sintering process at various sintering temperatures. The thermodynamic calculation and high-temperature X-ray diffraction results showed that Al element preferred to dissolve from the metastable Ti3AlC2 and diffused into Cu matrix to form Cu(Al) solid solution at temperatures ranging from 600 to 1000 °C. The TiCx→Ti3AlC2→Cu(Al) gradient interface features were in-situ produced in the sintered composites and thus contributed to the improvement of the microhardness and the compressive yield strength. The composite sintered at 1000 °C demonstrated the maximum microhardness of 161.6 HV0.2 and the maximum compressive yield strength of 348 MPa. In-situ tensile test inside SEM revealed that cracks generated from the edge of the specimen and extended along the interface between the Ti3AlC2 reinforcement and the Cu matrix. The present composite interface strategy will provide flexibility to optimize the interface microstructure and the overall properties of the metal matrix composites.