微量Ca对Mg-6Al-1Y-1Nd合金组织和性能的影响

Effect of Ca on microstructure and mechanical properties of Mg-6Al-1Y-1Nd alloy

利用感应熔炼制备了不同Ca含量的Mg-6Al-1Y-1Nd-xCa(x=0、0.1、0.4、0.7)镁合金,采用光学金相显微镜、扫描电镜、X射线衍射分析、能谱分析和拉伸及蠕变力学性能等手段研究了微量Ca元素添加对Mg-6Al-1Y-1Nd镁合金显微组织和力学性能的影响。研究结果证实,添加微量的碱土元素Ca使得Mg-6Al-1Y-1Nd镁合金的显微组织明显得到细化,Mg-6Al-1Y-1Nd合金主要存在Al_2Y和Al_2Nd块状稀土析出相,Ca元素的添加使得该合金形成了呈条状和骨骼状的新析出相Al_2Ca。力学性能测试结果证实微量Ca元素添加能够显著提高Mg-6Al-1Y-1Nd镁合金在室温和高温条件下的强度和塑性,同时显著提升了该合金在150～200℃/70 MPa测试条件下的抗蠕变性能,表明Ca是Mg-6Al-1Y-1Nd镁合金重要强化添加元素。

Mg-6 Al-1Y-1Nd-xCa(x=0,0.1,0.4,0.7)magnesium alloys were prepared through induction melting.Effect of minor content of Ca on microstructure and mechanical properties of Mg-6Al-1Y-1Nd alloy was investigated by using optical microscopyand scanning electron microscop,energy dispersive spectroscopy,X-ray diffraction and tensile and creep tests.The results show that the microstructure of Mg-6Al-1Y-1Nd magnesium alloy is evidently refined with the minor addition of alkaline earth element Ca.The block Al2Y and Al2Nd phases can be observed in the microstructure of Mg-6Al-1Y-1Nd alloy.With the addition of minor Ca in the alloy,the new rod and bone-shaped Al2Ca phase can be clearly observed also.The minor addition of Ca can markedly improve the strength and ductility properties at room and high temperatures of Mg-6Al-1Y-1Nd-x Ca alloys.Moreover,the creep properties of Mg-6Al-1Y-1Nd alloy at 150-200℃/70 MPa test condition are remarkably improved with the minor Ca addition also.The tensile and creep properties of Mg-6Al-1Y-1Nd alloys are effectively improved by the addition of Ca,which can be attributed to the microstructure refinement and the strengthen effect of phases.