Impacts of strain path on evolution of microstructures and texture of ECAP Zinc

Zinc (Zn) is of increasing interest for applications such as bioresorbable implants and zinc-ion batteries, but use is limited by poor mechanical performance. Equal channel angular pressing (ECAP) offers a potential solution, yet its influence on Zn’s crystallographic texture and associated properties including corrosion, dendrite formation, and interfacial behaviours, remains insufficiently understood. This study examines the evolution of microstructure, texture, and slip activity in Zn processed by four standard ECAP routes, referred here as RA, RB A , RB C , and RC. A single ECAP pass produced considerable grain refinement, while further passes gave more limited refining effects and led to route dependent differences in microstructural uniformity and dislocation densities. Severe plastic deformation by ECAP led to broad engagement of basal, prismatic, and pyramidal modes with the contributions from the different modes varying across pressing sequences and between routes. The Y- and B-fibre textures developed in the first pass, while the subsequent textural evolution was strongly influenced by the strain path. RB A and RB C strengthened the Y-fibre at the expense of the B-fibre, in association with 90° billet rotations used for these routes, which led to increased engagement of higher-order pyramidal slip systems to accommodate enhanced c-axis strains. For RC, alternating iso-planar shear imparted by this route led to sustainment of the initially formed Y-fibre dominated texture. Meanwhile, route A distinctively strengthened the B-fibre as 90° intersecting shear planes formed under this strain path promoted continual favourable realignment of input basal planes to the applied shear. Overall, ECAP route strongly influenced the microstructures and textures developed in Zn, which has direct implications for tailoring its performance for biomedical and energy-storage applications. • Strain path strongly directs evolution of Zn microstructures and texture in ECAP. • A single ECAP pass halves grain size while the route controls texture and uniformity. • Alternating iso-planar shear for route C preserved the initial Y- and B-fibre textures • ECAP routes B C and B A strengthen the Y-fibre and suppress the B-fibre texture. • Route A uniquely strengthens B-fibre due to progressive realignment of basal planes.