挤压变形态Mg-5Li-3Al-2Zn-xY合金的显微组织和力学性能

Microstructure and Mechanical Properties of As-extruded Mg-5Li-3Al-2Zn-xY Alloy

利用OM,XRD,SEM等方法研究Mg-5Li-3Al-2Zn-xY合金经过挤压后的显微组织和力学性能。结果表明:合金在挤压过程中发生了动态再结晶,出现了大量等轴晶,晶粒明显细化;合金中AlLi相被挤碎,并呈现出沿着挤压方向分布;当Y含量增加到2.0%(质量分数)后,AlLi相消失;挤压后合金的抗拉强度最高为326.3MPa。细晶强化和第二相强化是提高合金抗拉强度的2个主要因素,Al2Y含量,尺寸及分布决定着第二相强化作用的强弱。

The microstructure and mechanical properties of as-extruded Mg-SLi-3A1-2Zn-xY alloy were investigated by optical microscope, scanning electron microscope, and X-ray diffraction. The results show that the grains of the alloy were refined due to the dynamic recrystallization, and the A1Li phases were broken and distributed along the extrusion direction during the extrusion process. The A1Li phase disappeared when the Y content increased to 2.0wt%. The highest tensile strength of the alloy reaches 326.3MPa after extrusion. Fine grain strengthening and secondary phase strengthening are the two dominant factors for improving the ultimate strength of the alloy. The effect of secondary phase strengthening is determined by the content, size and distribution of A12Y