Effects of temperature of HIP process on characteristics of Inconel 718 superalloy

The present study focuses on the effects of the temperature of the hot isostatic pressing (HIP) procedure on Inconel 718 superalloy. HIP temperatures used were 1150, 1175, 1180 and 1205°C. HIP pressure was maintained at 1000 bar (98-6 MPa) and the soaking time was 2 h. Both room and high temperature tensile and bending tests were used to evaluate the effects of HIP temperature on Inconel 718 superalloy. Porosity tests and microstructural examination were performed. The results showed that the optimum HIP process temperature for 718 superalloy is 1180°C. Processing at this temperature can significantly reduce porosity and improve the microstructure segregation of Inconel 718 superalloy. Under these conditions, the superalloy showed an 18-28% increase in tensile strength at room temperature, a 7.38% increase at 540°C, and a 3.84% increase at 650°C. The elongation increased by 55.6% at room temperature, 109.71% at 540°C, and 19.91% at 650°C. Finally, the results of three-point bending tests showed that hipping at 1180°C can enhance the bending strength by 39.5% at room temperature and 13.83% at 540°C.