The experimental results is shown as followings : ( 1 ) the cyclic flow stress - strain curves in an incremental step test could be expressed as the power law relation : ( 2 ) when the strain amplitude is lower during cyclic deformation tests under constant strain control , softening firstly appears , then gradually hardens with the increasing numbers of cycle ; when the strain amplitude is higher , hardening firstly appears , then gradually softens 试验结果表明： ( 1 )循环流变应力与应变的相互关系曲线均符合幂律关系式： ( 2 )在室温下进行恒应变幅循环变形过程中，当所控制的应变幅较小时，该材料首先出现循环软化，之后随循环周次的增加直至循环失效前该材料出现了硬化现象。当应变幅较大时，该材料开始出现硬化，然后随循环周次的增加才出现软化。
