Improving the mechanical properties and inhibiting strain softening behavior of the biodegradable Zn-0.06Mg alloy via ECAP plus rolling processing

Abstract

The practical application of micro-alloying Zn–Mg alloys is limited due to their poor mechanical properties and evident strain softening behavior. Therefore, this paper proposed the utilization of ECAP plus rolling processing as an innovative approach to potentially address these limitations. Herein, effects of ECAP and rolling processing on the microstructures, mechanical properties and strain softening behavior were investigated. It was found that the grain refinement achieved through 1-pass ECAP and 8-pass ECAP processing differed significantly, and subsequent rolling processing can further regulate grain size and dislocation distribution. The 1-pass ECAP plus cold rolling (1p-CR), 1-pass ECAP plus hot-cold rolling (1p-HC), and 8-pass ECAP plus hot-cold rolling (8p-HC) processed alloys exhibited heterostructure characterized by fine grains encircling coarse grains. Additionally, regions with high density dislocations were uniformly distributed alongside regions with low density dislocations. This unique microstructure promoted the accumulation and interaction of dislocation during deformation, resulting in the inhibition of strain softening behavior while maintaining high strength and high elongation. Therefore, the 1p-CR, 1p-HC, and 8p-HC alloys demonstrated excellent formability and mechanical stability while meeting the required mechanical properties for implant materials, which highlight their significant potential for practical applications.