Mg2Si强化相对AZ31镁合金挤压组织与力学性能的影响

Effect of Mg2Si phase on microstructure and mechanical properties of as-extruded AZ31 magnesium alloy

通过Al-Si中间合金取代Al添加,并经热挤压成形,在AZ31镁合金中引入Mg2Si强化相。采用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射分析(XRD)、电子万能试验机等研究了Mg2Si强化相对AZ31镁合金挤压组织与力学性能的影响。结果表明,添加Al-Si中间合金后的Mg-3(Al-Si)-Zn挤压组织呈现明显的双峰分布特征,Mg2Si颗粒相可通过粒子激发形核(PSN)作用促进动态再结晶,在碎化的Mg2Si颗粒相周围,合金组织显著细化,形成明显异于其他正常尺寸晶粒的细晶区。引入Mg2Si强化相后,Mg-3(Al-Si)-Zn挤压态合金的屈服强度和抗拉强度都得到提高,分别达到175和269 MPa,同时伸长率略有降低。

Mg2Si phase was introduced into AZ31 magnesium alloy by replacing Al with Al-Si master alloy combined with hot extrusion.Effect of Mg2Si phase on the microstructure and mechanical properties of AZ31 magnesium alloy was studied by optical microscope( OM),scanning electron microscopy( SEM),X-ray diffraction analysis( XRD) and electronic universal testing machine. The results show that the Mg-3( Al-Si)-Zn extrusion microstructure presents obvious bimodal distribution,and the Mg2Si particle phase can promote dynamic recrystallization by particle stimulated nucleation( PSN),and the microstructure is refined dramatically around Mg2Si particles. The yield and tensile strength of Mg-3( Al-Si)-Zn alloy are improved to 175 MPa and 269 MPa,respectively,while the elongation decreases slightly after the introduction of Mg2Si strengthening phase.