单晶镍基高温合金蠕变曲线的预测

Creep curve prediction of single crystal nickel-based superalloy based on θ projection concept

根据单晶镍基高温合金蠕变过程的微观机制,提出采用θ蠕变曲线方程对其进行蠕变曲线的预测.首先,应用该方法对1 100℃1、50 MPa下的实测蠕变曲线进行拟合;然后,依据不同条件下的拟合结果求出方程中5个基本参数的数学表达式,再通过θ蠕变曲线方程对合金在1 100℃、120 MPa条件下的蠕变曲线进行预测.结果显示,该方程很好地再现了单晶镍基高温合金蠕变曲线的前两个阶段,其精度是以往预测方法所不能达到的.表明,用本方法预测单晶镍基高温合金的蠕变寿命具有实际意义,文中给出的θ蠕变曲线方程是可以信赖的.

Based on the micro-mechanism of the creep, a θ creep curve equation was proposed to predict creep curves for the single crystal nickel-based superalloy. Firstly, the creep curve measured at 1 100 ℃ and 150 MPa was fitted. According to the fitted result, the temperature and stress dependence of the five material constants in the equation was established. Then, the creep curve at 1 100 ℃ and 120 MPa was predicted. The results show that for the single crystal nickel-based superalloy, the proposed equation can well describe the two stages of the creep curve with a satisfactory accuracy. The accuracy of this methodis the best in some predicted method. It is recognized that this method should be useful for predicting the creep life of single crystal nickel-based superalloy.