Aging temperature role on precipitation hardening in a non-equiatomic AlCoCrFeNiTi high-entropy alloy

In the present study, the influence of aging temperature on precipitation hardening in a non-equiatomic Al0.2Co1.5CrFeNi1.5Ti0.3 high-entropy alloy has been evaluated. The aging curves have been deduced for different aging temperatures (650, 750, and 850°C) as a function of time. The aging response was found to be markedly different with varying aging temperatures. A combined FESEM and transmission electron microscope studies have been performed to understand the evolution of precipitates and their characteristics with aging temperature and time. The variation of precipitate morphology, number density and size of precipitates with aging temperature were correlated with the age-hardening response. Additionally, the role of lattice misfit strain on precipitate morphology has been evaluated.