Effect of Heat Treatment on Microstructure and Properties of GH3536 Fabricated by Selective Laser Melting

Selective laser melting (SLM) forming technology to prepare nickel-based superalloy parts can significantly save costs and solve bottleneck problems. The extremely high-temperature gradient and large residual stress during SLM lead to structural defects and compositional segregation. The parts formed by SLM urgently need heat treatment to control the microstructure composition and improve mechanical properties. Results showed that the heat treatment did not significantly change the microcracks and pores in the SLM sample, but the carbides in the grain boundary gradually changed from a granular distribution to a continuous strip distribution. After heat treatment, the elongation increased significantly, but the yield strength decreased. The tensile fracture of the SLM samples changed from a transgranular fracture to a ductile fracture, and obvious plastic deformation occurred, confirming that heat treatment can improve the benefits of the SLM sample.