Abstract
? 2022 Elsevier B.V.In this study, a new grade of Inconel 718 alloy (IN718) strengthened by nano-oxides has been designed and produced. The alloy composition of 0.3 wt% Y2O3 – IN718 has been determined using CALPHAD-based thermochemical modeling approach. Designed ODS-IN718 alloy is produced by Selective Laser Melting (SLM) method with various power and velocity values to determine the best process parameters for this system. The SLM parameters are optimized for the production of ODS-IN718 alloy. 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'/γ″, 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 exhibit the best microstructural and mechanical properties. Tensile tests demonstrate that the strength and ductility of the solutionized and aged samples are much improved compared to the standard solutionized and double aged samples due to the fine and uniform microstructure, especially at elevated temperatures. It is observed that experimental results are consistent with the thermochemical modeling calculations. This clearly shows the promise of thermochemical calculations incorporating various databases for designing new alloy systems with nano-oxide strengthening.
NSTL
Elsevier