(1. 中国民航大学 理学院 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)
摘 要: 采用密度泛函理论计算研究Zr和(或)Mn替位掺杂γ-TiAl形成的8个合金体系的几何结构、形成能、弹性模量、能带结构和重叠布居数等。结果表明：各个掺杂体系的总能量和原子平均形成能均是负值，表明它们具有较好的能量稳定性、在特定条件下是可以实验制备的。Zr或(和)Mn单(双)替位掺杂可以改善此类γ-TiAl基合金体系的轴比(R)和弹性模量比(B/G)，特别是Ti12Al11Zr、Ti12Al11Mn、Ti11MnAl11Zr和Ti11ZrAl11Mn的轴比更接近于1，B/G接近1.75，预报这4个掺杂体系均具有较好的延性。这为探索改善γ-TiAl基合金的延性提供了理论依据。根据对典型掺杂体系电子性质和重叠布居数分析，发现Zr和Mn掺杂使体系的共价键强度降低、金属键强度增强，从而提高了面间的可动性，有利于改善合金的延性。
关键字: γ-TiAl基合金；Zr掺杂；Mn掺杂；延性；电子性质；第一性原理
（1. Institute of Low Dimensional Materials and Technology, College of Science,
Civil Aviation University of China, Tianjin 300300, China;
2. Sino-European Institute of Aviation Engineering, Civil Aviation University of China, Tianjin 300300, China）
Abstract:8 kinds of γ-TiAl based alloys doped with Zr and (or) Mn were investigated with density function theory. The geometric structures, formation energies, elasticity modulus, band structures and overlap populations were analyzed. The results indicate that these systems possess energy stability and can be made with experiment at certain condition because of their negative total energies and atomic average formation energies. Zr and (or) Mn doping can change the axis ratios (R) and elastic moduli ratios (B/G) of the 8 systems. It is forecasted that systems of Ti11MnAl11Zr, Ti12Al11Zr, Ti12Al11Mn, and Ti11ZrAl11Mn possess good ductibility for their axis ratios are close to 1 and moduli ratios are close to 1.75, which provides theoretical support for improving ductibility of γ-TiAl based alloys. Based on the obtained electronic properties and overlap population, it is argued that the doping of Zr and (or) Mn can make the decrease of covalent bond intension and the increase of metal bond intension, resulting in the improving mobility of the crystal face, which is propitious to the improvement of the intermetallic ductility.
Key words: γ-TiAl based alloy; Zr doping; Mn doping; ductibility; electronic property; first-principles
