Micro-Embossing Formability of a Superlight Dual-Phase Mg-Li Alloy Processed by High-Pressure Torsion

Micro-embossing tests are performed on a coarse-grained (CG) and an ultrafine-grained (UFG) dual-phase Mg-Li alloy processed by high-pressure torsion (HPT) using different widths of the female die at ambient temperature under a force of 9 kN. The surface topography, rib profiles, and microstructures of the cross-sections are measured by scanning electron microscopy, confocal scanning laser microscopy, and optical microscopy, respectively. The interactive effects of the cavity widths of the female die and dual phases on the formability of micro-embossing are analyzed. Numerical simulations are performed to study the effects of the dual-phases on the filling behavior of the CG and UFG alloys. The results show that a UFG Mg-Li alloy reduces the adverse effects of dual phases on the formability of micro-embossing. Micro-channel arrays with channel widths ranging from 50 to 200 mu m are fabricated with good geometrical accuracy using a UFG dual-phase alloy at ambient temperature, thereby establishing the excellent potential for using UFG dual-phase Mg-Li alloys processed by HPT for applications in micro-forming.