This paper discusses suitable strain and stress low-cycle fatigue (LCF) parameters for Alloy 738LC, a Ni-based superalloy, under tension–torsion loading at 1173 K. Tension–torsion proportional LCF tests were performed using the superalloy at two strain rates. Five strain and four stress parameters were applied to estimate LCF life at the two strain rates. Suitable strain parameters for multiaxial LCF life correlation are discussed in relation with the stress response. The linear damage rule based on von Mises equivalent strain and stress is used to estimate the creep–fatigue lives of the alloy with reasonable accuracy.

中文翻译：

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镍基高温合金 738LC 的拉伸-扭转多轴蠕变-疲劳寿命

本文讨论了合金 738LC（一种镍基高温合金）在 1173 K 的拉扭载荷下的合适应变和应力低周疲劳 (LCF) 参数。使用高温合金在两种应变率下进行了拉扭比例 LCF 测试。应用五个应变和四个应力参数来估计两个应变率下的 LCF 寿命。讨论了与应力响应相关的多轴 LCF 寿命相关性的合适应变参数。基于 von Mises 等效应变和应力的线性损伤规则用于以合理的精度估算合金的蠕变疲劳寿命。