Microstructures and Mechanical Properties of the TiC/CM247LC Nickel-Based Composite Fabricated by Selective Laser Melting: Effect of Heat Treatment

In this study, TiC/CM247LC nickel-based composite was successfully prepared by selective laser melting, then was heat treated at a solid solution temperature of 1260 °C and different aging temperature of 840 °C, 870 °C, 900 °C and 930 °C respectively. Effects of aging temperatures on the microstructures and mechanical properties were systematically studied. The results show that the microstructures of all the heat treated samples are composed of γ matrix, carbides and γ′ phase. The γ grains remain a columnar shape after treatments, but the size of γ′ phase grows up gradually with the increasing aging temperature. The composite treated at an aging temperature of 870 °C exhibits the best mechanical properties with the tensile strength of 1073 MPa, yield strength of 1004 MPa and elongation of 7.57%. The plastic deformation and strengthening mechanisms of heat treated composite were systematically investigated.