INVESTIGATION OF THE EFFECT OF SLM PARAMETERS ON THE MICROSTRUCTURE OF A HEAT-RESISTANT NICKEL ALLOY

The influence of the parameters of selective laser melting (SLP) with high-temperature heating of the platform to 1000 °C on the formation of the microstructure of heat-resistant nickel alloy GTD-111 has been studied. It was found that varying the scanning parameters (linear and volumetric energy density) has not significantly affect the size of the γ'-phase secretions. However, a regular spatial heterogeneity of the microstructure was revealed: in the lower layers of all samples exposed to prolonged high-temperature exposure, the initial stage of formation of the raft structure (elongated particles of the γ'-phase) was observed. It was shown that this process was a consequence of particle coagulation under the influence of platform heating temperature and internal stresses, which was similar to the initial stage of alloy degradation under creep conditions. The results of the work are important for the development of SLP modes for monocrystalline products, such as gas turbine blades, in order to control their structure and operational properties.