Preparation, microstructure, and mechanical behaviour of Ni3Al-based superalloy reinforced with carbide particles

Abstract

The preparation, microstructure, and mechanical behaviour of Ni3Al-based superalloy have been studied. The superalloy reinforced with carbide particles forming in-situ in the melt was prepared by vacuum induction melting (VIM) followed by centrifugal casting. The as-cast alloy was subjected to heat treatment consisting of solid solution annealing, quenching, and ageing. The microstructure of the heat-treated superalloy consists of blocky MC carbides (6.9 vol%), which are uniformly distributed within the columnar grains containing cuboidal γ′(Ni3Al) precipitates (57.3 vol%) embedded in the γ (Ni-based solid solution) matrix and along γ′ grain boundaries. The equivalent plastic strain distribution in the plastic zone underneath Vickers macroindentation and within the compression specimens deformed to engineering strains ranging from 0.05 to 0.27 is calculated using finite element analysis (FEA). The correlation curve between experimentally measured Vickers microhardness values and calculated equivalent plastic strains has been proposed to quantify the level of local strain hardening state of the studied Ni3Al-based superalloy. The room temperature compressive strain hardening behaviour is evaluated and measured strain hardening exponent and strain hardening rate are discussed.