Microstructure and mechanical behavior of Inconel 625 alloy processed by selective laser melting at high temperature up to 1000 °C

Mechanical behavior of Inconel 625 alloy manufactured by selective laser melting (SLM) was experimentally studied. Tensile tests were performed at various temperatures (20, 540, 760, 815, 870, 950 and 1000 degrees C). The microstructures and fracture mechanism were investigated using optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The SLM Inconel 625 exhibits excellent plastic deformation at low temperature. However, significant embrittlement for the SLM Inconel 625 was found at elevated temperatures compared to low temperature and traditional forging process. Through microstructure studies, the non-homogenous microstructure is a key factor causing the intergranular cracking mode at elevated temperature. Moreover, carbides were found to form at the grain boundary at elevated temperatures. These carbides could weaken the strength of the grain boundary at elevated temperatures, which decreased the tensile strength and ductility of the alloy processed by SLM. Graphic abstract