Effect of cumulative strain on the microstructural and mechanical properties of Zn-0.02 wt%Mg alloy wires during room-temperature drawing process

Zn-0.02Mg alloy wires with cumulative area reduction of up to 97% were prepared by multi-pass drawing at room temperature. Microstructure evolution indicated that the deformation mechanism was initially dominated by both dislocations and {10 (1) over bar2} twins, then gradually only by dislocations. Dynamic recrystallization (DRX) occurred as the cumulative area reduction exceeded 45%. The DRX resulted in significant grain refinement and formation of equiaxied grains in size of 1 mu m in the wires with a diameter of 0.8 mm. Drawing deformation made the texture transform from ED parallel to<01<(1)over bar>0> to DD parallel to<0001>, while the DRX resulted in texture with DD deviating 70 degrees away from <0001>. Both yield strength and tensile strength increased from 136 MPa to 167 MPa for the as-extruded Zn-0.02Mg alloy to 388 MPa and 455 MPa for the as drawn wire with a diameter of 0.8 mm, while the elongation decreased from 27% to 5.4%. The variation of mechanical behaviors meant possibility for regulating both the strength and elongation of the Zn-Mg alloy wires in a wide range by optimizing the drawing technology. (C) 2018 Elsevier B.V. All rights reserved.