Mg-Y-Nd合金{1011}孪晶界面稀土原子偏聚的电子显微研究  

Electron microscopy study of the segregation of RE solute atoms to {1011} twin boundaries in Mg-Y-Nd alloy

作　　者：李万鹏[1] 刘翠秀[1] 陈斌[1] 毕建军 孙威[1] LI Wan-peng;LIU Cui-xiu;CHEN Bin;BI Jian-jun;SUN Wei(Institute of Microstructure and Property of Advanced Materials,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学固体微结构与性能研究所,北京100124

出　　处：《电子显微学报》2018年第6期563-570,共8页Journal of Chinese Electron Microscopy Society

基　　金：国家自然科学基金资助项目(No.11274027)

摘　　要：本文综合利用电子显微镜表征手段对冷轧后时效处理Mg-4Y-3Nd(wt.%)合金中[1102](1101)共格孪晶界面的稀土溶质原子偏聚行为进行研究,发现在经423 K+5 h时效后,合金中Nd元素在孪晶界面存在明显的偏聚析出,而Y元素的偏聚则并不明显。这表明镁合金中固溶的Nd原子相较Y原子具有更高的扩散速率和向{1011}孪晶界偏聚析出的驱动力。另外,本实验还揭示了相较于共格孪晶界面,孪晶界面上存在的孪晶台阶具有较大的晶格错配,稀土溶质原子优先选择在孪晶台阶处偏聚。The feature of segregation of rare earth atoms on the[1102](1101)twin boundary in the cool-rolled and aged Mg-4Y-3Nd(wt.%)alloy has been investigated by means of various electronic microscopic characterizations.It is found that soluted Nd atoms are preferable to solute Y atoms for segregating at twin boundary after ageing at 423 K for 5 hours.This result strongly indicates that the Nd atom in the Mg matrix has a higher diffusion rate and a higher driving force for segregation to the{1011}twin boundary in comparison with the Y atom.In addition,it is also revealed that the twin steps at twin boundary involve more pronounced lattice misfit in contrast to the coherent twin boundary,and this leads to preferential segregation of rare earth solute atoms to the twin steps.

关 键 词：Mg-Y-Nd合金 (1101)孪晶 时效 溶质原子偏析 电子显微表征 

分 类 号：TG146[一般工业技术—材料科学与工程] TG115[金属学及工艺—金属材料]