(1. 蘭州理工大學 數(shù)字制造技術與應用省部共建教育部重點實驗室，蘭州 730050；
2. 蘭州理工大學 機電工程學院，蘭州 730050；
3. 蘭州工業(yè)學院 機電工程學院，蘭州 730050)
摘 要: 采用軸向應變控制的方法，研究Ti-43Al-9V-0.3Y合金材料在550 ℃時不同應變量條件下的高溫低周疲勞行為。通過Manson-Coffin公式分析循環(huán)應力-應變和應變疲勞壽命，推導擬合出應變幅與疲勞壽命之間的關系式。分析試樣高溫低周疲勞斷口的形貌，得出β/γ三相鈦鋁基合金的高溫低周疲勞的機理。結果表明：Ti-43Al-9V-0.3Y合金的應變疲勞的過渡疲勞壽命循環(huán)周次約為49，合金的循環(huán)應力響應行為取決于外加總應變幅，合金疲勞行為具有循環(huán)軟化特性，彈性變形是該合金低周疲勞的主要因素。
關鍵字: 鈦鋁合金；應變控制；疲勞壽命；疲勞行為
（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
