【摘要】 采用金相、X射线衍射、扫描电镜和透射电镜等方法对两种不同Mn含量应变诱发孪晶(TWIP)钢拉伸前后的显微组织进行了研究。结果表明,Fe-15Mn-3Si-3Al钢的塑性增长机理主要是γfcc→hεcp,fγcc→hεcp→αbcc相变诱发的TRIP效应;Fe-25Mn-3Si-3Al钢主要的塑性增长机制是孪晶诱发的TWIP效应。Fe-25Mn-3Si-3Al钢拉伸后有些奥氏体晶粒内存在两个或多个孪晶系统,孪晶界与原始奥氏体晶界都会阻碍孪晶的长大。层错能强烈影响TWIP钢的变形机制,随着Mn含量的增加,层错能不断增加,孪晶强化逐渐起主导作用。更多还原

【Abstract】 Microstructure before and after deformation of two Fe-Mn-Si-Al TWIP steels containg different amount of manganese（15wt% and 25wt%） were investigated by optical microscope,X-ray diffraction,SEM and TEM.The results show that γ_fcc→ε_hcp and γ_fcc→ε_hcp→α_bcc phase transformation induces plasticity in the Fe-15Mn-3Si-3Al TWIP steel and there is no detected deformation twins.However,lots of deformation twins appeares in Fe-25Mn-3Si-3Al TWIP steel after tensile test,which greatly increases its plasticity.TEM results show that mechanical twinning and dislocation gliding interacts in grains,two or more twin systems are activated in most grains,twin and grain boundaries are strong obstacles for twins.Stacking fault energy （SFE） played an important role in twinning mechanism,with the increase of Mn content,SFE increases,and twinning mechanism is then favored.更多还原