Development and Additive Manufacturing of Oxide Dispersion Strengthened Inconel 718 : Thermochemical and Experimental Studies

In this study, a new grade of Inconel 718 alloy (IN718) strengthened by nano-oxides have been designed and produced. The alloy composition of 0.3 wt.% Y 2 O 3 – IN718 has been determined using CALPHAD based thermochemical modelling approach. Designed ODS-IN718 alloy is produced by Selective Laser Melting (SLM) method with various power and velocity values in order to determine the best process parameters for this system. The SLM parameters are optimized for production of ODS-IN718 alloy. In order to dissolve the non-equilibrium phases, which are detrimental to the mechanical properties, and maximize the number densities of nano-oxide and other strengthening phases of γ'/γʺ , various heat treatment processes are applied based on the thermochemical calculations. The samples which are solutionized at 1050 °C for 1 h followed by aging at 650 °C for 5 h exhibited the best microstructural and mechanical properties. It is observed that experimental results are consistent with the thermochemical modelling calculations. This clearly shows the promise of thermochemical calculations incorporating various data bases for designing new alloy systems with nano-oxide strengthening