Nb含量对TiAlNb金属间化合物塑性影响的计算研究  

TiAlNb Intermetallics Compound Plasticity by Substituting Nb for Ti

作　　者：李燕峰[1,2] 徐慧[1,2] 马松山[2] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083 [2]中南大学物理科学与技术学院,湖南长沙410083

出　　处：《稀有金属》2010年第S1期10-16,共7页Chinese Journal of Rare Metals

基　　金：湖南省自然科学基金项目(07JJ3102);长沙市科技计划项目(k0902132-11)资助

摘　　要：采用密度泛函的赝势平面波法,对(TiAl)1-xNbx(x=0,1/16,1/12,1/8,1/4)掺杂相的晶体进行了几何优化,计算了弹性常数、电子结构和布居数等,系统分析了掺杂对几何结构、电子结构和键强的影响机制。结果表明:Nb带来的几何变化对体系塑性性能的影响较小;随着Nb的增加,B/G值出现波动,当Nb含量为8.33%～12.5%体系塑性和各向同性性质较好;且随着Nb的增加,体系共价键强度大幅削减,Ti-Al和Nb-M(M=Ti,Al)等杂化键成分增强,在峰区增多的同时赝能隙先减小后增大,能带展宽整体变窄,降低了体系共价性和方向性,布居分析数据也表明空间成键的方向性得以均化,与电子结构分析一致。综上分析,当Nb摩尔含量在8.33%～12.5%时有利于室温塑性的改善。Based on the pseudopotential plane-wave method of density functional theory(DFT),the(TiAl)1-xNbx(x=0,1/16,1/12,1/8,1/4) crystals' geometry structure,elastic constants,electronic structure and mulliken populations were calculated,the effect of doping on the geometric structure,electronic structure and bond strength were systematically analysed.The results showed that the influence of Nb to the geometric structure causes little effect to the plastic;with the increase of Nb,B/G values fluctuate,the room temperature plasticity and isotropic of the system can be improved with the Nb mole content of 8.33% ～12.5%;with the increased of Nb,the covalent bond strength significantly reduced,Ti-Al and Nb-M(M=Ti,Al) and other hybrid keys which enhance;meanwhile,the Peak District increased and the pseudo-energy gap first decreases and then increases,the overall band structure which narrowed,the covalent bond and direction of bonds were reducing,population analysis data also showed that the results were consistent with the electronic structure analysis.All the calculations shows that the room temperature plasticity of the alloys can be improved with the Nb mole content of 8.33% ～12.5%.

关 键 词：TIAL 第一性原理 Nb掺杂 室温塑性 

分 类 号：TG146.15[一般工业技术—材料科学与工程]