By the combination of transmission electron microscope, neutron diffraction and small-angle neutron scattering methods, mechanical fatigue behavior of AL6XN austenitic stainless steel was investigated in the temperature range of 400–600 °C. At 400 °C, in addition to the occurrence of dynamic strain aging, the formation of short-range order was evidenced from the forbidden electron diffraction spot of 1/3 {422} in face-centered cubic (fcc) structure viewed down [111] zone axis, which facilitate the planar slip mode of dislocation and result in the work hardening during the fatigue deformation. The fatigue damage is mainly dominated by the accumulation of planar slip band and the interaction among various slip systems. With increasing temperature, precipitates of chi phase, Laves phase and sigma phase were formed during the fatigue tests at 500 and 600 °C. An increase in precipitation content at 600 °C has also been confirmed by both scanning electron microscope and small-angle neutron scattering analysis. The dislocation pileup originating from the uncoordinated deformation between precipitate and austenitic matrix is an important fatigue damage leading to crack. The continuous cycle softening behavior was also observed on the fatigue curve at 600 °C, which is considered to be caused by dynamic recovery.

中文翻译：

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AL6XN奥氏体不锈钢在高温下的疲劳损伤机理

通过透射电子显微镜，中子衍射和小角度中子散射方法的组合，研究了AL6XN奥氏体不锈钢在400–600°C温度范围内的机械疲劳行为。在400°C时，除了发生动态应变时效外，从面心立方（fcc）结构中向下观察的1/3 {422}的禁止电子衍射点也证明了短程有序的形成[111]。区域轴，这有利于错位的平面滑动模式，并导致疲劳变形过程中的工作硬化。疲劳损伤主要由平面滑带的积累和各种滑移系统之间的相互作用决定。随着温度的升高，of相的沉淀 Laves相和Sigma相在500和600°C的疲劳测试过程中形成。扫描电子显微镜和小角中子散射分析也证实了600°C时沉淀物含量的增加。源于沉淀物和奥氏体基体之间不协调变形的位错堆积是导致裂纹的重要疲劳损伤。在600°C的疲劳曲线上也观察到了连续的循环软化行为，这被认为是由动态恢复引起的。源于沉淀物和奥氏体基体之间不协调变形的位错堆积是导致裂纹的重要疲劳损伤。在600°C的疲劳曲线上也观察到了连续的循环软化行为，这被认为是由动态恢复引起的。源于沉淀物和奥氏体基体之间不协调变形的位错堆积是导致裂纹的重要疲劳损伤。在600°C的疲劳曲线上也观察到了连续的循环软化行为，这被认为是由动态恢复引起的。