钆对B2型NiAl力学性质合金化效应的第一性原理计算  

Mechanical Properties of B-NiAl Intermetallic Compound with Gadolinium Addition by First-Principles Calculation

作　　者：陈律[1] 李敏 刘逸众 Chen Lü;Li Min;Liu Yizhong(Aviation Electromechanical Equipment Maintenance Department,Air Force Institute of Aeronautical Maintenance Technology,Aviation Electromechanical Equipment Maintenance Department,Changsha Aeronautical Vocational and Technical College,Changsha 410124,China;Hunan Aircraft Maintenance Engineering Technology Research Center,Changsha 410124,China)

机构地区：[1]空军航空维修技术学院航空机电设备维修学院,长沙航空职业技术学院航空机电设备维修学院,湖南长沙410124 [2]湖南省飞机维修工程技术研究中心,湖南长沙410124

出　　处：《中国稀土学报》2020年第4期514-520,I0003,共8页Journal of the Chinese Society of Rare Earths

基　　金：湖南省自然科学基金科教联合基金项目(2017JJ5057)资助。

摘　　要：采用第一性原理赝势平面波方法,基于虚拟晶体势函数近似(VCA),研究了Gd微合金化(x<1.0%,原子百分比,下同)对理想与包含点缺陷B2-NiAl晶体的弹性常数C44,Cauchy压力参数(C12-C44)、弹性模量E、剪切模量G及其与体模量B0的比值G/B0随Gd合金化浓度x的影响。数据分析显示:无论Gd原子取代Ni原子位还是取代Al原子位,Gd微合金化能提高理想B2-NiAl晶体的硬度,同时也不利于其合金材料室温塑性的改善。微量Gd能与B2-NiAl多晶材料中的点缺陷协同作用,改善其合金的塑性,并以Gd原子取代Al位时效果明显,从而解释了实验研究中出现Gd微合金化能提高B2-NiAl合金压缩塑性的现象。Using the first-principles pseudopotential plane-wave methods based on the density functional theory,the elastic constant C44,Cauchy pressure(C12-C44),elastic modulus E,shear modulus G and their ratio G/B0 of B2-(Ni1-xGdx)Al and B2-Ni(GdxAl1-x)(x=0~1.0%,atom fraction)supercells with or without Ni vacancy or Ni anti-site defect are calculated in the framework of Virtual Crystal Approximation.Either Gd atoms replace Ni atom site or Al atom site in perfect NiAl crystal,the hardness of perfect B2-NiAl crystal can be improved,but the room temperature ductility can not be improved with the increase of Gd alloying concentration.Gd can work in concert with the point defects in B2-NiAl polycrystalline materials to improve the ductility of NiAl materials,replace Al site with Gd atom especially.The above results explained the reason why Gd microalloying is beneficial to improving the room temperature plasticity of NiAl materials in experimental studies.

关 键 词：B2-NiAl Gd合金化 第一原理计算 VCA近似 弹性性质 

分 类 号：TG146.2[一般工业技术—材料科学与工程]