(1. 北京科技大学 材料科学与工程学院，北京 100083； 2. 钢铁研究总院 华东分院北京研发中心，北京 100081； 3. 北京航空材料研究院，北京 100095)
摘 要: 利用第一性原理计算了Ti-35Nb(质量分数，%)合金的广义层错能，并讨论了合金中Nb原子占位对β→ω相变的影响。结果表明：在β相中沿{112}á{Lai, 2015 #5}111？滑移系开动会引起β→ω相变，形成ω相和孪晶相间隔的“三明治”结构，包含最近邻Nb原子链的{112}á{Lai, 2015 #5}111？滑移系的临界剪切应力约是2126.46 MPa，应力诱发的ω相最小尺寸约是长2.6444 nm，厚1.1297 nm；而包含次近邻Nb原子链的{112}á{Lai, 2015 #5}111？滑移系的临界剪切应力约是180.21 MPa，ω相最小尺寸约是长1.304 nm，厚0.3766 nm，较容易开动。
关键字: Ti-35Nb合金；β→ω相变；原子占位；广义层错能
（1. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing100083, China; 2. Center of Beijing R&D, East China Branch of Central Iron and Steel Research Institute, Beijing 100081, China; 3. Beijing Institute of Aeronautical Materials, Beijing 100095, China）
Abstract:The generalized stacking fault energy was calculated by the first-principles and the influence of Nb atoms occupancy on the induced β→ω phase transformations was discussed in Ti-35Nb (mass fraction, %) alloy in this work. The results show that the opening of {112}{Lai, 2015 #5}á{Lai, 2015 #5}111？systems in β phase can form ω phase alternated along twinning so called “sandwich” structure. Meanwhile the critical shear stress of {112}á{Lai, 2015 #5}111？ slip systems including the nearest neighbor Nb atoms chains is 2126.46 MPa in perfect crystal, and form the minimum ω phases with 2.6444 nm in length and 1.1297 nm in width. Furthermore, the critical shear stress of {112}á{Lai, 2015 #5}111？ slip systems including the next nearest neighbor Nb atoms chains is 180.21 MPa in perfect crystal, further, the minimum ω phase has 1.304 nm in length and 0.3766 nm in width.
Key words: Ti-35Nb alloy; β→ω phase transformation; Nb atoms occupancy, generalized stacking fault energy
