高锰无磁钢的循环变形特征及其机制

研究了高锰无磁钢的循环变形特征，以及微观组织结构的变化。发现当应变幅较低(1/2Δεt为0.25%和0.5%)时，室温下出现循环软化，但在低温下循环硬化；当应变幅较高(1/2Δεt＝1.0%)时，在室温和低温下均循环硬化。实验材料的软化与IS结合体被破坏而产生的软化相符；循环硬化来源于形变马氏体的产生，在较高应变幅下还包括奥氏体基体的位错硬化。

CHARACTERISTICS AND MECHANISMS OF CYCLIC DEFORMATION OF HIGH MANGANESE NONMAGNETIC STEEL

The cyclic deformation characteristics and microstructural changes of high manganese nonmagnetic steel have been studied. It was found that the experimental material showed cyclic softening at room temperasture but cyclic hardening at low tempertures when the strain amplitudes were relatively low(1/2Δεt =0.25%),0.5%, but only cyclic hardening was showed at room or low temperatures when the strain amplitude was relatively high(1/2Δεt =1.0%).The cyclic softening of the experimental material consisted with the softening which was resulted in by the decomposition of IS complexes. The cyclic hardening was due to the formation of deformation-induced martensite, and the effect of distocation hardening of the austenite martrix under relatively high strain amplitude.