Influence of Hot Extrusion Process on Microstructure and Mechanical Properties of Mg-Zn-Y-Zr Magnesium Alloy

Abstract

The extrusion experiments at different extrusion parameters were performed; the effects of different extrusion parameters on the microstructure and mechanical property of Mg-4.8Zn-1.2Y-0.4Zr magnesium alloy were described, based on the experimental results and analysis. The result shows that dynamic recrystallization is observed after the hot extrusion process, the alloy grain is refined compared with as-cast alloy. The phase of the extruded alloy is W-phase; there are great differences in morphology and distribution between alloys with different extrusion parameters. The microstructure and mechanical properties of magnesium alloy are affected by extrusion temperature and extrusion ratio in the hot extrusion process. When the extrusion ratio is the same, the number of recrystallization grains increases with the increasing of temperature; meanwhile recrystallization grains also have a tendency to grow up. When the extrusion temperature is 300 °C, the comprehensive mechanics performance of the alloy is the most excellent. The influence of extrusion ratio on the plasticity of the alloy is obvious; when the extrusion ratio is 25, the elongation of the alloy increases significantly.