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

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.

Automated summary

This study introduces a heterogeneous lamella (HL) structure in ZK60 alloy fabricated using conventional powder metallurgy techniques. The HL structure consists of soft coarse-grained (CG) lamella embedded in a hard ultrafine-grained (UFG) matrix, resulting in a synergistic combination of strength and elongation.