Hierarchical multi-phase microstructural architecture for exceptional strength-ductility combination in a complex concentrated alloy via high-temperature severe plastic deformation

Modification of a coarse B2 phase and realization of hierarchical multi-phase microstructures were achieved in an Al0.5CrFeCoNi complex concentrated alloy (CCA) using high-temperature severe plastic deformation (HTSPD). Under HTSPD conditions, a thermodynamically stable B2 phase dissolved, while a thermodynamically unstable coarse Al3Ni phase formed. Al supersaturation in the matrix after HTSPD led to the formation of fine B2 precipitates during the subsequent aging treatment. The combination of Al3Ni for enhanced work hardening and fine B2 precipitates for strength resulted in excellent strength-ductility of 1400 MPa and 20%. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.