对国产核电用Inconel690高温合金在25，200，350℃进行了应变和应力循环加载下的单轴和多轴疲劳试验，分析了其循环应力-应变响应及循环塑性变形特性。结果表明：在试验温度下，无论是单轴还是多轴加载，Inconel690高温合金均主要表现出循环硬化特性，棘轮应变在初始数个循环周次内快速增长，最后迅速达到稳定；在25℃和200℃单轴应变循环一定周次后Inconel690高温合金呈现出轻微的循环软化特性；在多轴循环加载条件下，合金存在较为明显的非比例多轴附加硬化现象。

Uniaxial and multi-axial fatigue tests with strain-controlled and stress-controlled loading modes at 25, 200, 350℃ were conducted on domestic Inconel690 superalloy for nuclear power. The cyclic stress-strain response and cyclic plastic deformation characteristics were analyzed. The results show that at the test temperatures, the Inconel690 superalloy mainly exhibited cyclic hardening characteristics in both uniaxial and multi-axial loading processes. The ratcheting strain imcreased rapidly in the first few number of cycles and finally reached stable quickly. The Inconel690 superalloy exhibited slight cyclic softening characteristics when the uniaxial strain-controlled loading cycled in a certain number of cycles at 25 and 200℃. Under multi-axial cyclic loading conditions, an obvious non-proportional multi-axial additional hardening was observed.