A new deformation mechanism via bidirectional transformation between γ-austenite and ε-martensite [B-transformation-induced plasticity (TRIP)] provides a great possibility to develop fatigue-resistant steel due to its high reversibility in dislocation motion. The Fe-18Mn-11Cr-7.5Ni-4Si B-TRIP steel was designed by modifying the previously developed Fe-15Mn-11Cr-7.5Ni-4Si steel. Strain-controlled fatigue test was conducted at the total strain range of 1%, and newly developed steel demonstrated two-fold fatigue life (21,994 cycles in average) compared with the previous one. Microstructural analysis after fatigue fracture showed that the enhanced irreversible α’-martensitic transformation at the crack tip in the previous steel negatively affected fatigue durability by locally invaliding B-TRIP.

通过 γ-奥氏体和 ε-马氏体之间双向相变的新变形机制 [B-相变诱导塑性 (TRIP)] 由于位错运动的高可逆性，为开发耐疲劳钢提供了巨大的可能性。Fe-18Mn-11Cr-7.5Ni-4Si B-TRIP钢是在以前研制的Fe-15Mn-11Cr-7.5Ni-4Si钢的基础上进行改型设计而成。在 1% 的总应变范围内进行应变控制疲劳试验，新开发的钢材的疲劳寿命是以前的两倍（平均 21,994 次循环）。疲劳断裂后的微观结构分析表明，先前钢中裂纹尖端不可逆 α'-马氏体相变的增强通过使 B-TRIP 局部失效而对疲劳耐久性产生负面影响。