(1. 北京科技大學(xué) 材料科學(xué)與工程學(xué)院，北京 100083； 2. 鋼鐵研究總院 華東分院北京研發(fā)中心，北京 100081； 3. 北京航空材料研究院，北京 100095)
摘 要: 利用第一性原理計(jì)算了Ti-35Nb(質(zhì)量分?jǐn)?shù)，%)合金的廣義層錯(cuò)能，并討論了合金中Nb原子占位對(duì)β→ω相變的影響。結(jié)果表明：在β相中沿{112}á{Lai, 2015 #5}111？滑移系開動(dòng)會(huì)引起β→ω相變，形成ω相和孿晶相間隔的“三明治”結(jié)構(gòu)，包含最近鄰Nb原子鏈的{112}á{Lai, 2015 #5}111？滑移系的臨界剪切應(yīng)力約是2126.46 MPa，應(yīng)力誘發(fā)的ω相最小尺寸約是長2.6444 nm，厚1.1297 nm；而包含次近鄰Nb原子鏈的{112}á{Lai, 2015 #5}111？滑移系的臨界剪切應(yīng)力約是180.21 MPa，ω相最小尺寸約是長1.304 nm，厚0.3766 nm，較容易開動(dòng)。
關(guān)鍵字: Ti-35Nb合金；β→ω相變；原子占位；廣義層錯(cuò)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
