中文摘要：

综述了新型高温结构材料TiAl合金的高周疲劳行为基本特征,包括疲劳极限、疲劳强度和应力-寿命行为。分析TiAl合金高周疲劳S-N曲线特点发现,TiAl合金不具有疲劳极限,合金成分和组织形态是影响TiAl合金疲劳强度的关键因素。总结不同温度下的TiAl合金高周疲劳性能发现,当温度由韧-脆转变温度以下提高至该温度以上时,合金的高周疲劳寿命对循环应力变化的敏感性得到了明显改善。此外,还着重讨论了TiAl合金层片组织的疲劳寿命波动性问题,认为层片组织的随机取向是影响疲劳裂纹形核和小裂纹扩展过程的关键因素,从而导致合金高周疲劳寿命产生明显波动。根据该波动机理,探讨了增加TiAl合金高周疲劳寿命、降低其波动性的组织优化途径。

英文摘要：

TiAl alloys are a class of intermetallic alloys that show potential as a high-temperature structural material.Many applications considered for TiAl alloys require certain high-cycle fatigue behavior characteristics.Herein,the fatigue properties of TiAl alloys,namely fatigue limit,fatigue strength and stress-life behavior are reviewed,to assess the current understanding of fatigue behavior in this emerging material.According to the reported S-N curves of TiAl alloys,the fatigue limit characteristics of this new material and the critical influences on fatigue strength are analyzed and commented on.The variation laws of fatigue life during high-cycle fatigue regime with cyclic loading below and above ductile-brittle transition temperature are summed up.Moreover,with greater emphasis on fatigue life variability and the main reason for this phenomenon,an optimization approach to increase high-cycle fatigue life and reduce its variability is discussed.