Understanding creep behaviour in high performance alloys through use of the Wilshire equations

This study explores the creep behaviour of three polycrystalline alloys—stainless steel 316, Haynes 282, and Inconel 713C—chosen for their varying precipitate volume fractions. The primary aim is to provide a comprehensive understanding of the underlying mechanisms that control creep behaviour in these alloys, with a particular focus on determining the creep activation energies (Qc*) involved. SS316 displays a gradual transition in Qc* values, attributed to dislocation movement at low temperatures and twinning above yield stress at elevated conditions. Haynes 282 shows a wider range (277–427 kJ/mol), with γ′ precipitate resistance at low stress and forest hardening above yield stress. In contrast, Inconel 713C with highest volume fraction of precipitates, exhibits a constant Qc*, indicating creep governed by confined dislocation motion within γ channels, with no clear transition. The findings reinforce the application of the Wilshire equations in rationalising Qc* values and linking them to microstructural mechanisms. This provides a robust framework for predicting creep behaviour, aiding alloy development and high-temperature material optimisation.