Microstructural evolution and mechanical properties of pure zinc subjected to extrusion and caliber rolling

Abstract

This study investigates the microstructural evolution and mechanical properties of pure zinc (Zn) during extrusion and multi-pass caliber rolling (CR). Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) analyses indicate that plastic deformation induces dynamic recrystallization (DRX), resulting in the formation of numerous low angle grain boundaries (LAGBs) and substructures. In particular, significant grain refinement (∼1.6 μm) is achieved with the texture deviating 30 ± 5° from the <0001> direction. The as-extruded pure Zn exhibits a yield strength (YS) of 130 MPa, an ultimate tensile strength (UTS) of 151 MPa, and an elongation (EL.) of 8.8 %, respectively. Subsequent caliber rolling significantly improved these mechanical properties (i.e., YS: 225 MPa; UTS: 301 MPa; EL.: 31%) due to the combined effect of grain refinement, dislocations and texture strengthening. In addition, the deformation mechanism shifts from an initial influence of both dislocations and twins to a predominance of dislocations alone.