Influence of rolling deformation on the microstructure and mechanical property of as-extruded Zn-0.5Cu-0.05Ti-0.05 Mg microtubes

Zinc(Zn) alloys are ideal candidates for biodegradable stent materials owing to their good strength and ductility, appropriate degradability and acceptable biocompatibility. A novel Zn-0.5Cu-0.05Ti-0.05Mg microtube with an outer diameter of 3.5 mm and a wall thickness of 0.2 mm was manufactured using the combination of hot-extrusion with subsequent cold-rolling route. As-rolled microtubes exhibit enormous difference in microstructures and mechanical performances compared to their as-extruded counterpart. As anticipated, the grains are refined from 1.94 ± 1.05 μm for as-extruded sample to 0.99 ± 0.63 and 0.85 ± 0.35 μm for as-rolled samples with deformations of 45 and 86 %, respectively. Concurrently, the strong basal texture present in as-extruded alloy is weakened, evolving into two-component textures of RD (rolling direction)‖<-1103> and RD‖<11–23> in as-rolled microtube with 45 % deformation, and weak deformation textures with RD‖<0001> and non-basal texture RD‖<25–73> in as-rolled microtube with 86 % deformation. Consequently, as-rolled microtubes present remarkable work softening and enhanced plasticity. It is elucidated that the grain size smaller than the critical grain size and the weakened basal texture play a critical role in strength reduction and elongation to break enhancement in as-rolled microtubes. Our research provides insights into the processing, microstructures and properties of Zn-0.5Cu-0.05Ti-0.05Mg alloy, which are instructive for the fabrication of Zn-based biodegradable microtubes with optimized mechanical properties.