(1. 中國民航大學 理學院 低維材料與技術(shù)研究所，天津 300300；
2. 中國民航大學 中歐航空工程師學院，天津 300300)
摘 要: 采用密度泛函理論計算研究Zr和(或)Mn替位摻雜γ-TiAl形成的8個合金體系的幾何結(jié)構(gòu)、形成能、彈性模量、能帶結(jié)構(gòu)和重疊布居數(shù)等。結(jié)果表明：各個摻雜體系的總能量和原子平均形成能均是負值，表明它們具有較好的能量穩(wěn)定性、在特定條件下是可以實驗制備的。Zr或(和)Mn單(雙)替位摻雜可以改善此類γ-TiAl基合金體系的軸比(R)和彈性模量比(B/G)，特別是Ti12Al11Zr、Ti12Al11Mn、Ti11MnAl11Zr和Ti11ZrAl11Mn的軸比更接近于1，B/G接近1.75，預報這4個摻雜體系均具有較好的延性。這為探索改善γ-TiAl基合金的延性提供了理論依據(jù)。根據(jù)對典型摻雜體系電子性質(zhì)和重疊布居數(shù)分析，發(fā)現(xiàn)Zr和Mn摻雜使體系的共價鍵強度降低、金屬鍵強度增強，從而提高了面間的可動性，有利于改善合金的延性。
關(guān)鍵字: γ-TiAl基合金；Zr摻雜；Mn摻雜；延性；電子性質(zhì)；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
