A modified theta projection model for constant load creep curves-II. Application of creep life prediction

作者：Fu, Chao; Chen, Yadong; Yuan, Xiaofei; Tin, Sammy; Antonov, Stoichko; Yagi, Koichi; Feng, Qiang^*

来源：Journal of Materials Science & Technology, 2019, 35(4): 687-694.

DOI：10.1016/j.jmst.2018.09.035

• Superalloy
• Constant load creep
• Modified theta projection model
• Uniform deformation stage
• Prediction performance

To minimize the deviation of the predicted creep curves obtained under constant load conditions by the original theta projection model, a new modified version that can be expressed by epsilon = theta(1)(1 - e(-theta 2t)) + (e(theta 4e theta 5 epsilon t) - 1), was derived and experimentally validated in our last study. In the present study, the predictive capability of the modified theta projection model was investigated by comparing the simulated and experimentally determined creep curves of K465 and DZ125 superalloys over a range of temperatures and stresses. Furthermore, the linear relationship between creep temperature and initial stress was extended to the 5-parameter model. The results indicated that the modified model could be used as a creep life prediction method, as it described the creep curve shape and resulted in predictions that fall within a specified error interval. Meanwhile, this modified model provides a more accurate way of describing creep curves under constant load conditions. The limitations and future direction of the modified model were also discussed. In addition, this modified theta projection model shows great potential for the evaluation and assessment of the service safety of structural materials used in components governed by creep deformation.

• 出版日期2019-4
• 单位北京科技大学; 新金属材料国家重点实验室