Precipitation strengthening of ductile Cr15Fe20Co35Ni20Mo10 alloys

Non-equiatomic Cr15Fe20Co35Ni20Mo10 (Mo-10) high-entropy alloys (HEAs) are produced by arc-melting and subsequent thermal-mechanical processing. The single-phase Mo-10 HEA5 with face centered cubic (FCC) structure exhibit an exceptional ductility and strain hardening capability associated with twinning. Tailoring thermal-mechanical processing condition enables the evolvement of single-phase Mo-10 HEAs to multiphase microstructure that comprises simple FCC solid solution and nanoscale precipitates of Mo-rich is phase. These precipitates primarily grow at grain boundaries and twin boundaries, strengthening Mo-10 HEAs. This work sheds light on realizing a superb strength-ductility combination of HEAs by coupling solid solution hardening, nanotwinning and precipitation hardening mechanisms. (C) 2017 Published by Elsevier Ltd on behalf of Acta Materialia Inc.