Influence of Second-Phase Particles on GH3536 Nickel-Based Superalloy in Selective Laser Melting Process

GH3536 alloy, as a typical solid solution-strengthened, nickel-based high-temperature alloy, has been widely used in the preparation of hot-end components. In this paper, a nickel matrix composite (TiC + TiB2)/GH3536 reinforced with a mixture of submicron TiB2 particles and micron TiC particles was prepared using SLM technology, demonstrated a tensile strength of 1206 MPa and a microhardness of 469.7 HV, which are 85.9% and 86.1% greater than those of the unreinforced GH3536 alloy, and 17.5% and 37.3% higher, respectively, when compared to composites with only 3 wt.% micrometer TiC reinforcement. The effects of dual-phase and dual-size reinforcing particles on the machinability, microstructure, and mechanical properties of (TiC + TiB2)/GH3536 composites were systematically investigated, and the strengthening mechanisms were elucidated. The results indicate that, compared with the single addition of 3 wt.% micron TiC, the strengthening effect produced by adding 1.5 wt.% submicron TiB2 and 1.5 wt.% micron TiC is primarily achieved through fine grain strengthening and dislocation strengthening.