Synthesis of inconel 718 superalloy by electric current activated sintering

Abstract

In the present study, the production of Inconel 718 nickel based superalloy was carried out in an electric current activated sintering in open air under a uniaxial pressure of 300 MPa using Al, Ni, Fe, Cr, Ti, Co, Fe-Nb and Fe-Mo powders. This alloy was heat treated, following the conventional treatment which consists of a 1 h solution treated at 980 °C, followed by air cooling and double ageing, 8 h at 720 °C, furnace cooling at 55°C/h down to 620 °C and ageing for 8 h. Optical and SEM examinations showed a dense microstructure with low amount of porosity. XRD studies showed the existence of the γ and MC type carbide (M atom is a Nb, Ti combination) and δ phases. The relative density of sample measured according to Archimedes' principle was 93.7%, and the microhardness of sample was about 343.8 HV0.1.