Transmission electron microscopy of deformation induced martensite and deformation twins

• 作 者: ZHANGWeina;ZHANGZhibo;LIUZhenyu;WANGGuodong;
• 机 构: State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,Liaoning,Chin
• 出 处: 第五届宝钢学术年会
• 发表日期: 2013年期

　　The deformation induced martensite and deformation twins were investigated by transmission electron microscopy ( TEM) in high manganese TRIP/TWIP steels at different temperature.Because of the different temperature,the stacking fault energy ( Γ) was different.It was pointed out that when Γ< 10.0 mJ/m2,deformation mechanism was the deformation induced bcc-martensitic transformation;When 17.7 mJ/m2 < Γ < 36.4 mJ/m2,the competition mechanism between deformation twins and hcp-martensite phase transformation was main deformation mechanism;when 36.4 mJ/m2 < Γ < 41.9 mJ/m2,the governing deformation mode was crystallographic slip and deformation twin;when 41.9 mJ/m2 < Γ < 78.3 mJ/m2,the slipping was a predominant deformation mode.The orientation relationships in the deformation process were obtained.It was found that the martensitic transformation from metastable austenite proceeded in two steps.In the first step,hcp-martensite nucleated at stacking faults of metastable austenite.And then,the secondary hcp-martensite had been nucleated at stacking fault near deformation twins,and the bcc-martensite nucleated in the intersection of two hcp-martensite laths.The deformation nano-twins were observed to have been formed along the preferential hcp-martensite.