钛合金以其优异的性能迅速发展成为重大工程领域、高技术领域不可或缺的关键材料，其服役过程中的疲劳稳定性是研究热点之一。应力诱发马氏体相变在钛合金强韧化调控方面拥有巨大应用潜力。但是目前缺乏基于应力诱发马氏体相变的钛合金疲劳行为及机理的研究。本项目拟以亚稳β钛合金为研究对象，研究钛合金在交变载荷作用下的应力诱发马氏体相变行为；对钛合金进行疲劳试验，研究微观组织、加载温度对应力诱发马氏体相变和疲劳行为的影响规律；结合疲劳变形过程中的结构观察与应力分析，进一步明晰基于应力诱发马氏体相变的疲劳损伤微观机制，揭示相变-疲劳交互作用机理，建立基于微观相变的钛合金疲劳寿命预测模型。该项目探索利用微观相变提高金属材料疲劳性能的可能性，为钛合金的安全服役提供一定的指导，同时对丰富钛合金疲劳理论具有重要意义。

Due to excellent properties, titanium alloy has been selected as a critical material in various important projects and high technical fields. The fatigue stability of titanium alloy served in the process is also one of the hot points. The stress induced martensitic transformation in titanium alloy should have great potential in strengthening regulation. But in current, research on fatigue properties based on stress induced martensitic transformation in titanium alloys is rarely reported. In this regard, aimed at shortcomings of previous studies, the present project intends to prepare a series of metastable beta titanium alloys, investigate the stress induced martensitic transformation under alternating load. In different conditions, fatigue tests will be performed on titanium alloy, to study the influence of microstructure, loading temperature on the fatigue properties based on stress induced martensitic transformation. Combined with microstructure characterization and stress analysis of internal materials, the mechanism of fatigue crack based on stress induced martensitic transformation will be discovered. The response relations between phase transformation and fatigue performance will be analyzed and cleared. Then, the model of fatigue life will be estimated. This project tries to explore the possibility of using phase transformation to improve the fatigue property of metallic materials, and will provide a theoretical basis and an experimental support for the application of titanium alloys, it also has important meaning to rich the fatigue theory of titanium alloys.