Development of high-strength, low-cost wrought Mg-2.5 mass% Zn alloy through micro-alloying with Ca and La

A high-strength low-cost Mg-2.5Zn-0.3Ca-0.4La (mass%) alloy was fabricated by hot extrusion following directchill casting. Yield strength (YS), ultimate tensile strength (UTS) and elongation to failure of the alloy are 325 MPa, 341 MPa and 15%, respectively. The high strength of the extruded Mg-2.5Zn-0.3Ca-0.4La alloy is mainly clue to grain refinement, dense precipitation and high density of dislocations. The extruded alloy exhibits a bimodal microstructure containing fine dynamic recrystallized (DRXecl) grains and deformed regions. High density of dislocations is stored in the deformed regions while dense precipitates are homogeneously distributed in both the DRXecl grains and the deformed regions. However, precipitates in the DRXecl regions show in spherical shape only while they arc in rod-like shape and spherical shape in the deformed regions. (C) 2015 Elsevier Ltd. All rights reserved.