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.
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