Influence of constrained groove pressing and post-annealing on the mechanical, microstructural, and strain hardening behaviour of Nimonic 263 alloy

Abstract

This study investigates the impact of heat treatment on CGPed Nimonic 263 alloy, commonly used in marine engines and gas turbine applications. CGP refines the grain structure, while post-CGP aging at different temperatures influences mechanical properties and strain-hardening behavior. CGP increased yield strength and ultimate tensile strength by 218 % and 52 %, respectively, with post-CGP aging at 800 °C, further enhancing them by 266 % and 160 %. Vickers hardness also improved after CGP (59 %) and aging (88 %) compared to as-received material. Kocks-Mecking plot analysis showed distinct strain hardening behaviors, and fractography indicated brittle fracture in CGPed specimens and mixed-mode fracture in heat-treated samples. Aging at 800 °C proved most effective in enhancing Nimonic 263's microstructure and properties, broadening its potential use in gas turbine blades, discs, and combustors in aircraft. © 2024 Elsevier B.V.