取向相关的单晶高温合金低周疲劳寿命评估方法

In order to investigate the anisotropy of low⁃cycle fatigue (LCF) properties of single crystal (SC) superalloys, the LCF experimental data of SC7⁃14⁃6, DD3, PWA1480, Rene N4 and DD6 were collected from literatures.The calculation method of elastic modulus of SC superalloys was verified.The elastic modulus of different orientations was introduced to modify the total strain amplitude.A simple expression of LCF damage parameter was proposed, which was suitable for different crystallographic orientations of single crystal superalloys.Furthermore, an orientation⁃dependent LCF life evaluation method was formed.The experimental data of the above five alloys were used to validate this method.The results showed that:the elastic modulus was an important factor influencing the anisotropy of SC superalloys' LCF performance;the elastic modulus conversion method among different orientations in literature was reliable;most prediction results of the proposed method were within a factor of two.The proposed method is quite simple and effective, and it is suitable for engineering applications.