(1. 兰州理工大学 数字制造技术与应用省部共建教育部重点实验室，兰州 730050；
2. 兰州理工大学 机电工程学院，兰州 730050；
3. 兰州工业学院 机电工程学院，兰州 730050)
摘 要: 采用轴向应变控制的方法，研究Ti-43Al-9V-0.3Y合金材料在550 ℃时不同应变量条件下的高温低周疲劳行为。通过Manson-Coffin公式分析循环应力-应变和应变疲劳寿命，推导拟合出应变幅与疲劳寿命之间的关系式。分析试样高温低周疲劳断口的形貌，得出β/γ三相钛铝基合金的高温低周疲劳的机理。结果表明：Ti-43Al-9V-0.3Y合金的应变疲劳的过渡疲劳寿命循环周次约为49，合金的循环应力响应行为取决于外加总应变幅，合金疲劳行为具有循环软化特性，弹性变形是该合金低周疲劳的主要因素。
关键字: 钛铝合金；应变控制；疲劳寿命；疲劳行为
（1. Key Laboratory of Digital Manufacturing Technology and Application, Ministry of Education,
Lanzhou University of Technology, Lanzhou 730050, China;
2. School of Mechanical and Electronical Engineering, Lanzhou University of Technology, Lanzhou 730050, China;
3. School of Mechanical and Electronical Engineering, Lanzhou Institute of Technology, Lanzhou 730050, China）
Abstract:The high temperature low cycle fatigue behavior of Ti-43Al-9V-0.3Y alloy under condition of different strain amplitudes and 550 ℃ was studied by the method of axial strain control. Based on the formula of Manson-Coffin, the cyclic stress strain and the strain fatigue life were analyzed, and the formula between amplitude and fatigue life was deduced and fitted. After analyzing the fracture morphologies of high temperature low cycle fatigue fracture of sample, the mechanism of high temperature low cycle fatigue of β/γ three-phase TiAl alloy was obtained. The results show that the transition fatigue life cycles of strain fatigue of Ti-43Al-9V-0.3Y is about 49. Cyclic stress response depends on the applied total strain amplitude, and the fatigue behavior has the cyclic softening characteristics.
Key words: TiAl alloy; strain control; fatigue life; fatigue behavior
