高温合金循环蠕变及其寿命预测

CYCLE CREEP OF SUPERALLOY AND ITS LIFE PREDICTION

当使用应变模型或应变能模型进行蠕变疲劳寿命预测时,通常情况下,寿命预测所需的几个应变分量是从应力—应变闭合的滞后环分解来获得。然而,循环蠕变的应力—应变滞后环是半开环,在这种情况下,本文首先叙述了各个应变分量通过实验方法直接测量来获得,而不能从这样的滞后环来得到,此外,本文还叙述了高温合金循环蠕变行为。最后讨论了用几个寿命预测模型对国内外十种材料的预测结果。预测结果表明,与 SEP,SRP,OM,FM 计算方法相比较,SEP—NCM 预测准确性是最好的。

Creep-fatigue life prediction was conducted using strain models or strain en- ergy models.Several strain components which are necessary to predict,were ob- tained from decomposition of stress-strain closed hysteresis loop.However,hys- teresis loop is half open loop for cycle creep.In this case,present paper will describe that the strain components were obtained by means of direct experimen- tal measurement,and can not be got from the loop.The cycle creep behaviour of su- peralloy also were described.Finally,for ten superalloys at home and abroad, prediction results according to several life prediction models were discussed.It showed that predicting accuracy of SEP-NCM is the best compared with compu- tational results of SEP,SRP,OM,FM models.