Low-temperature creep mechanism in ultrafine-grained aluminum

Abstract

This study investigated the low-temperature creep mechanisms in ultra-fine grained aluminum made by accumulative roll bonding. The low-temperature creep behaviors in ultra-fine grained aluminum with grain size of 0.39 µm were divided into four regions by three certain stress values, σ_my, σ_multi and σ_y. σ_my is stress for dislocation movement, σ_multi is stress for dislocation multiplication, and σ_y is yield stress. First, below σ_my, plastic deformation was negligible. Second, from σ_my to σ_multi, creep deformation with n=2.5 occurred by grain boundary sliding. Third, from σ_multi to σ_y, creep deformation with n=7.2 occurred by intragranular recovery of dislocations. Last, above σ_y, power-law breakdown was confirmed.