抗高温蠕变性能较差是限制钛合金在高温下应用的"瓶颈"。如何提高蠕变抗力是高温钛合金设计中亟待解决的关键问题之一。钛合金稳态蠕变的主要机制为位错攀移和原子扩散。降低位错运动和原子扩散速率能有效提高合金的蠕变抗力。位错运动速率与位错结构(位错宽度)、弥散析出相(如硅化物)的阻碍作用有关，其中，位错宽度决定于层错能大小；析出相的形成与弥散度与合金原子间的相互作用能有关。原子扩散速率决定于扩散激活能。这些因素均难以用实验手段准确测定，尽管已有大量钛合金蠕变性能的实验研究报道，但对合金化影响钛合金蠕变抗力的机理及规律仍缺乏本质认识。本项目拟采用第一原理方法，计算钛合金的层错能、合金原子间相互作用能、合金原子的扩散激活能，以揭示合金化影响钛合金蠕变性能的机理及规律，在理论上确定几种能提高钛合金蠕变性能的合金元素并进行实验验证，为实现钛合金蠕变性能的成分优化设计提供理论基础。

Poor creep resistance is a "bottle neck" of the high-temperature applications of titanium alloys. One of the key issues of the design of high-temperature titanium alloys is to improve the creep resistance. The main mechanisms of the steady-state creep of titanium alloys are the dislocation climb and atomic diffusion. The creep resistance may be enhanced efficiently by reducing the mobility of the dislocations and the atomic diffusion rate. The mobility of the dislocation is related to the dislocation structure (width of the dislocation) and the drag of the precipitates such as silicides. The width of the dislocation is in turn determined by the stacking fault energy whereas the formation of the precipitate is related to the interactions between the alloying atoms in the alloy. The atomic diffusion rate is determined by the activation energy for the diffusion. These factors can hardly be accurately measured experimentally. Therefore, fundamental knowledge of the alloying effects on the creep properties of titanium alloys is still limited although vast experimental research has been performed and reported in literature. In this project, we propose to investigate the alloying effect on the stacking fault energy of titanium alloys, the interaction energy between alloying atoms, as well as the diffusion activation energy by using first-principles methods based on electronic structure theory. The aim of this study is to reveal the mechanisms and rules of alloying effects on the creep property of titanium alloy, and, based on which, to identify theoretically alloying elements which may improve the creep resistance. The results of this project may help the rational design of high-temperature titanium alloys.