【摘要】 在Mg-9Al-1Zn合金的基础上添加不同质量分数的Yb,制备了4种合金。通过X射线衍射、金相显微镜、扫描电镜及能谱分析仪等手段分析了Yb的添加对AZ91D显微组织和力学性能的影响。结果表明:Yb的加入,显著改变了AZ91D合金的铸态组织,细化了β-Mg17Al12相,且β-Mg17Al12脆性相由连续网状分布逐渐变为离散状,同时晶界上出现了块状的Al11Yb3和点状Al6Mn4Yb化合物。当Yb含量为1.0%时,该合金具有最佳的综合力学性能,抗拉强度达到194 MPa,比AZ91D提高22%,伸长率和硬度也随着Yb含量的增加而提高。研究表明,重稀土元素Yb在镁合金中显示出与轻稀土更相近的作用效果。更多还原

【Abstract】 The effect of Yb on microstructures and mechanical properties of Mg-9Al-1Zn alloys containing varied contents of Yb was studied.The X-ray diffraction,optical microscopy,scanning electron microscopy and energy disperse spectroscopy were used to analyze microstructures and mechanical properties of the alloys.The result showed that the addition of a small amount of Yb to AZ91D alloys refined the continuous β-Mg17Al12 phase,which became the separate shape gradually and synchronously.The compounds Al11Yb3 and Al6Mn4Yb were discovered on grain boundaries.The tensile properties of the as-cast alloys containing 1%Yb exhibited the highest tensile strength,and its tensile strength achieved 194 MPa and enhanced to 22% comparing with AZ91D. The elongation ratio and hardness increased with the addition of Yb.The research showed that Yb had a similar effect with the light rare earths in magnesium alloy.更多还原