Influence of Processing Regimes on Fine-Grained Microstructure Development in an Al–Mg–Sc Alloy by Hot Equal-Channel Angular Pressing

Abstract

Grain refinement during equal-channel angular pressing (ECAP) was studied in a commercial Al–5.8%Mg–0.3%Sc alloy at temperatures from 473 to 723 K (∼0.5–0.8T_m). The samples were quenched in water in every ECAP pass, which is a conventional cyclic process. ECAP to ε = 12 resulted in ultrafine-grained structures developed uniformly at high strains at 473 and 723 K, while processing at 573 K led to the evolution of a duplex grain structure containing partially much coarser grains. In contrast, ECAP process continuously carried out to ε = 12 without interruption at 573 K, resulted in development of a uniform ultrafine-grained structure. Effects of processing regimes on microstructural evolution in the Al–Mg–Sc alloy are discussed.