Enhanced Strength-Ductility Synergy of Mg-6Zn Alloy Wire by Inducing Guinier-Preston Zone Precipitation

This article designs a strategy of introducing ultrafine precipitates into single-phase microstructure to enhance Mg-6Zn alloy wire. Three combined processes including equal channel angular pressing (ECAP), direct extrusion, and multipass drawing are used to produce 0.3 mm-diameter wire. The results show that an isothermal process of ECAP, extrusion, and drawing at 32 degrees C (named route B) produces a near-fully solid solution microstructure and causes a very high elongation of 21% as well as an ultimate tensile strength of 24 MPa. Furthermore, on this basis, the addition of an aging treatment before drawing induces the precipitation of the Guinier-Preston zone in the near-single-phase Mg matrix and improves the tensile elongation to 28%, and the ultimate tensile strength also is increased to 290 MPa. Based on severe plastic deformation-induced homogenization and aging-induced precipitation of Mg-Zn alloy, a novel isothermal extrusion-drawing process causes the formation of high density of Guinier-Preston zones and dislocations in near-single-phase microstructure. This achieves high strength-ductility synergy, with an ultimate tensile strength of 290 MPa and an elongation of 28% in Mg-6Zn alloy wire.image (c) 2024 WILEY-VCH GmbH