基于对 3 16L不锈钢多轴非比例循环加载低周疲劳微结构的研究结果 ,测量了位错自由运动间距 ,分析了位错自由运动间距的分布规律 ,给出了位错自由运动间距统计平均值与宏观等效饱和应力幅值之间的关系 ,以位错自由运动间距统计平均值给出了应变路径非比例度的定义 .在单轴循环应力 -应变关系式中引入新的非比例度的定义可以较好地描述多轴非比例循环应力 -应变行为 Based on the results of 3-16L stainless steel multi-axial non-proportional cyclic loading low cycle fatigue microstructures, the free movement spacing of dislocation was measured, the distribution of dislocation free movement spacing was analyzed, and the statistical average value of dislocation free movement spacing And the macro-equivalent saturated stress amplitude, the definition of the non-proportional strain path is given by the statistical mean value of the free movement spacing of dislocations.A new non-proportional degree is introduced into the uniaxial cyclic stress-strain relation The definition can well describe multi-axis non-proportional cyclic stress-strain behavior