Achieving high strength and high ductility in ZK60 alloy with a heterogeneous lamella structure

摘要

Heterogeneous structure emerges as a novel design philosophy for metal materials to break through the strength -ductility tradeoff. Here we present a heterogeneous lamella (HL) structure in ZK60 alloy that was fabricated by conventional powder metallurgy techniques, i.e., powder pretreatment and hot extrusion. The distinctive structure consists of soft coarse-grained (CG) lamella embedded in the hard ultrafine-grained (UFG) matrix. Compared to the homogeneous CG and UFG counterparts, the HL ZK60 alloy exhibits an excellent combination of tensile yield strength (404.4 MPa) and uniform elongation (13.5 ). This strength-ductility synergy can be attributed to the hetero-deformation induced (HDI) strengthening and HDI strain hardening as a result of the deformation incompatibility and mutual constraint between the hetero-zones.