Influence of Surface State on Mechanical Properties of Selective Laser Melting GH3536 Alloy

GH3536 alloy longitudinal and transverse samples were prepared by selective laser melting. After heat treatment and hot isostatic pressing treatment, some samples were machined into smooth-surface samples. The influence of surface state on tensile and fatigue properties was studied by comparing with build-surface samples. The results show that there was little difference in the longitudinal room temperature tensile properties between smooth-surface samples and build-surface samples, so the surface state had no significant effect on the tensile properties. Compared with that of smooth-surface samples, the strain fatigue life of build-surface samples was slightly lower, and the stress fatigue life of build-surface samples was significantly reduced, which was 2%-8% of smooth-surface samples. The cracks in the crack source region of the smooth-surface samples were radially shaped, those in the propagation region were vein-like, and there were a lot of dimples in the instantaneous fracture region. There were no obvious radial cracks in the build-surface samples, which was multi-source cracking, and the fracture was cleavage fracture.