Zr和(或)Nb掺杂γ-TiAl合金的延性与结构稳定性  

Investigations on ductibility of Zr and(or) Nb doped γ-TiAl based alloys

作　　者：宋庆功[1,2] 杨宝宝[1] 赵俊普[1] 郭艳蕊[1] 胡雪兰[2] SONG Qinggong YANG Baobao ZHA O Junpu GUO Yanrui HU Xuelan(Institute of Low Dimension Material and Technology, College of Science Sino-European Institute of Aviation Engineering, CA UC, Tianjin 300300, China)

机构地区：[1]中国民航大学低维材料与技术研究所,天津300300 [2]中国民航大学中欧航空工程师学院,天津300300

出　　处：《中国民航大学学报》2016年第6期55-60,共6页Journal of Civil Aviation University of China

基　　金：国家自然科学基金项目(51201181);中央高校基本科研业务费专项(3122015K001)

摘　　要：采用密度泛函理论结合物理化学分析,计算了Zr和(或)Nb替位掺杂γ-Ti Al形成的8个合金体系的几何结构、能量性质、弹性性质、电子性质和化学键特性。结果表明:各个掺杂体系的总能量和原子平均形成能均为负值,表明其具有较好的稳定性。掺杂体系Ti12Al11Zr、Ti12Al11Nb、Ti11Nb Al11Zr和Ti11Zr Al11Nb的轴比都有所改善,更接近于1。对单掺杂体系和双掺杂体系,晶胞体积的变化与杂质原子半径的变化趋势一致,且Zr和Nb总是都倾向于替代Ti原子;掺杂体系均具有较好的延性,为改善γ-Ti Al基合金的延性提供了理论依据;Zr和Nb掺杂使体系的共价键强度降低、金属键强度增强,体系的能量稳定性有所降低,因而提高了面间的可动性,有利于改善合金的延性。Eightγ-TiAl based alloy systems doped with Zr and （or） Nb are investigated by using first-principles method based on the density function theory combined with physical chemistry theory. Their geometric structures, energy properties, elastic properties, electronic properties and chemical bond properties are calculated and analyzed. Results indicate that the stability of these systems can be confirmed with their negative total energies and atomic average formation energies. The axis ratios of system Ti12Al11Zr, Ti12Al11Nb, Ti11NbAl11 Zr and Ti11ZrAl11Nb are all close to 1, the improvement is distinct. The change tendency of unit volume is in accordance with the radius of doping atom in single-doping and co-doping systems, in addition, Zr and Nb are always inclined to substitute Ti atoms. These doped systems all possess better ductility, presenting theoretical supporting points for the efforts to improve the ductility of γ-TiAl based alloys. It is presented that the doping of Zr and Nb makes the decreased intension of covalent bond while the increased intension of metal bond, resulting in the stability of these alloy decreased slightly. Therefore, it can improve the mobility of crystal face, which is favorable for improving the alloys＇ ductility.

关 键 词：Γ-TIAL基合金 Zr和(或)Nb掺杂 延性 电子性质 第一性原理 

分 类 号：TG146.2[一般工业技术—材料科学与工程]