Effect of extrusion temperature on microstructure, mechanical properties, and deformation mechanism of Mg-2.5Er-0.6Zr alloy

Abstract

Different extrusion temperatures (350 °C, 380 °C, 410 °C) were used to forward extrude the cast Mg-2.5Er-0.6Zr (wt.%) alloy. The effects of extrusion temperature on the microstructure, mechanical properties, deformation texture and extrusion deformation mechanism of Mg-2.5Er-0.6Zr alloy were studied by OM, SEM, room temperature tensile test, EBSD and IGMA analysis. The results show that the cast alloy has coarse grains and exhibits random texture characteristics. After extrusion, the alloy underwent dynamic recrystallization (DRX), and the equiaxed grains were refined, forming a special rare earth texture, and the mechanical properties of the alloy were greatly improved. In the temperature range of 380 °C–410 °C, with the increase of extrusion temperature, the alloy grain coarsing, strength and plasticity gradually decrease, but it is still much higher than the cast alloy. Under the combined influence of fine grain strengthening, texture weakening and diversified plastic deformation modes, the comprehensive mechanical properties of extruded Mg-2.5Er-0.6Zr alloy are the best at 380 °C, and its ultimate tensile strength, tensile yield strength and elongation are 218.7 MPa, 184.2 MPa and 44.1%, respectively.