2A70高强铝合金疲劳性能研究
周思奇1，张虹1，吴新涛2
（1.北京理工大学 机械与车辆学院，北京 100081；2.中国北方发动机研究所，天津 300400）
摘要：为探究2A70高强铝合金疲劳性能，开展了2A70应力比R＝-1温度T＝25℃与T＝150℃的高周疲劳试验。结合微观组织观测、应力－寿命（S－N）曲线绘制、典型断口观测，对其疲劳性能进行了研究。结果表明：温度升高会降低2A70高强铝合金的疲劳性能，温度为25℃和150℃时的疲劳极限分别为150 MPa和90 MPa；在常温和高温条件下都发生表面失效，裂纹萌生于次表面夹杂；2A70在疲劳加载过程中的主要断裂模式为解理断裂，在断口表面可以观察到大量河流花样和解理台阶。
关键词：2A70铝合金；微观组织；S－N曲线；失效机理
中图分类号：TH142.2 文献标志码：A doi：10.3969/j.issn.1006-0316.2020.05.007
文章编号：1006－0316 (2020) 05－0040－05
Study on the Fatigue Properties of 2A70 High-Strength Aluminum Alloy
ZHOU Siqi1，ZHANG Hong1，WU Xintao2
( 1.School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; 2.China North Engine Research Institute, Tianjin 300400, China )
Abstract：In order to investigate the fatigue properties of 2A70 high-strength aluminum alloy, a high cycle fatigue test with stress ratio R=-1 and temperature T=25℃ and T=150℃ was carried out. Combined with microstructure observation, stress-life (S-N) curve and typical fracture observation, the fatigue properties of 2A70 was investigated and the influence of temperature was analyzed. The results show that the fatigue properties of 2A70 high-strength aluminum alloy decrease with the increase of temperature, and the fatigue limit is 150 MPa and 90 MPa when the temperature is 25℃ and 150℃, respectively. The surface failure occurs at both room temperature and high temperature, and the crack initiates at the subsurface inclusions. The main fracture mode of 2A70 in the process of fatigue loading is cleavage fracture, and a large number of river patterns and cleavage steps can be observed on the fracture surface.
Key words：2A70 aluminum alloy；microstructure；S－N curve；fatigue failure mechanism
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收稿日期：2019－11－15
作者简介：周思奇（1996－），男，湖南长沙人，硕士研究生，主要研究方向为机械材料与结构的疲劳可靠性，E-mail：bitzhousq@163.com。
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