Effect of heat treatment on high temperature tensile properties of selective laser melting GH3536 alloys

Selective laser melting（SLM）can achieve nearly net-shape complex parts of GH3536 alloy，and its high temperature mechanical properties are important indicators for safe service. The effect of heat treatment on microstructure and high temperature tensile properties of SLM GH3536 alloy were studied. The heat treatment at 1225 ℃ for 1 h was carried out to explore the regulation mechanism of microstructure and properties. The results show that heat treatment can effectively eliminate the cellular subgrain structure inside the grains，which significantly enhances the dislocation slip ability. The tensile elongations at room temperature，650 ℃ and 815 ℃ are increased by 75%，92% and 683%，respectively. In addition，the decrease of the aspect ratio of the columnar grains significantly reduces the anisotropy in the heat-treated sample. The fracture analysis shows that the fracture mode of the heat-treated sample changes from intergranular fracture to mixed fracture with the increase of tensile environment temperature.