Effect of extrusion processing parameters on microstructure of Mg-Zr alloys

The micro-alloying effect, mechanical properties, and plastic deformation behavior of extruded Mg-Zr alloy were investigated and characterized as a function of Zr addition, grain size, and texture. The experimental methodology used in this study was design to exploit the hot-extrusion processing parameters (in the terms of extrusion ratios and temperature) and its effect on Mg extruded alloys microstructure, texture, and mechanical properties. Microstructural observations revealed significant grain refinement through a combination of Zr addition and hotextrusion, producing fine equiaxed grain structure with grain sizes ranging between 1-5 μm. Texture analysis and partial compression testing results showed that the initial texture of the extruded alloy gradually evolved upon compressive loading along the c-axes inducing contraction twinning creating a strong basal texture along the extrusion direction. Full tensile and compression test at room temperature showed that the combination of hot-extrusion and Zr addition can further refine the grains of the Mg alloys microstructure and enhance the texture while simultaneously enhancing the mechanical properties.