二元稀土镁合金Mg-La和Mg-Nd的组织和性能  

Investigation on the Properties of Mg-La and Mg-Nd Binary Magnesium-Rare Earth Alloys

作　　者：薛山[1] 孙扬善[1] 朱天柏 强力峰 陶立[1] 白晶[1] 

机构地区：[1]东南大学材料科学与工程系,江苏南京210096 [2]南京云海特种金属有限公司,江苏南京211221

出　　处：《铸造》2005年第9期888-891,共4页Foundry

基　　金：国家863项目(No.2001AA331030-01);江苏省自然科学基金(No.BK2004208)

摘　　要：系统研究了二元稀土镁合金Mg-2%La(L2)和Mg-2%Nd(N 2)的铸态显微组织、拉伸性能和抗蠕变性能。通过研究发现,L2铸态组织中有大量网状的Mg-Mg17La2的共晶相析出;而N2则以Mg12Nd离异共晶析出,析出物的数量少得多。N2合金在室温或者175℃条件下,强度和塑性都优于L2合金。N2合金的抗蠕变性能在175℃、70MPa条件下比L2低近3个数量级。通过计算两种合金的应力指数和蠕变激活能,L2合金的蠕变机制是受晶界滑动控制的,而N2合金为位错攀移机制控制。The as-cast microstructure, tensile properties and creep resistance of binary magnesium alloy Mg-2%La （L2） and Mg-2%Nd （N2） are studied thoroughly in the present investigation. The results showed that large quantity of Mg-Mg17La2 eutectic phase precipitated as network in as-cast microstructure of L2; in the as-cast microstructure of N2, however, Mg12Nd phase precipitated as divorced eutectic form and the volume fraction of precipitation was much less than that in L2. The strength and plasticity of N2 were higher than that of L2 both in ambient temperature and in 175 ℃. The creep resistance of N2 was nearly three orders of magnitude lower than that of L2 in 175℃, 70 MPa. It can be inferred the creep mechanism of L2 and N2 was controlled by grain boundaries sliding and dislocation climb respectively through the calculation of stress exponent and creep activation energy.

关 键 词：固溶强化 蠕变 应力指数 晶界滑动 位错攀移 二元稀土镁合金 

分 类 号：TG113[金属学及工艺—物理冶金]