Superior strength-ductility synergy of a cost-effective AlCrFe2Ni2 high entropy alloy with heterogeneous microstructure processed by moderate cryo-rolling and annealing

摘要

The effect of moderate cryo-rolling (similar to 65 reduction) and annealing on microstructure and mechanical properties of a cobalt-free (FCC + B2) AlCrFe2Ni2 high entropy alloy (HEA) was investigated. The cryo-rolled HEA showed a nanocrystalline structure with profuse nano-twins and stacking faults. The lamellar structure gradually transformed into a complete microduplex structure with increasing annealing temperature. The remarkably heterogeneous microstructure at the intermediate annealing temperature consisted of a mix of lamellar and microduplex domains and showed strength-ductility synergy superior to other cobalt-free HEAs. The present results established the efficacy of moderate cryo-rolling in tailoring heterogeneous microstructure and tensile properties of HEAs.