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利用光学显微镜、透射电镜、X射线衍射和相变仪对热镀锌TRIP钢的微观组织进行了定性观察和定量计算,在此基础上对热镀锌TRIP钢残留奥氏体的演变规律和马氏体的精细结构进行了研究。定性观察表明热镀锌TRIP钢的微观组织由铁素体,贝氏体,残留奥氏体和马氏体构成,在贝氏体相变结束后的冷却过程中还存在马氏体相变;通过对微观组织计算发现,受贝氏体等温相变时间影响,热镀锌TRIP钢中的马氏体碳含量在0.80%~1.0%之间,贝氏体等温时间越长,最终组织中马氏体碳含量越高,Ms点越低;在贝氏体相变结束后,部分碳含量不高的奥氏体在随后的冷却过程中发生马氏体相变,以马-奥岛的形式存在,马氏体的精细结构以孪晶马氏体为主,存在少量位错马氏体。
The microstructure of hot-dip galvanized TRIP steel was qualitatively observed and quantified by optical microscopy, transmission electron microscopy, X-ray diffraction and phase change instrument. On the basis of this, the microstructure evolution of retained austenite in hot-dip galvanized TRIP steel and horse The fine structure of the body has been studied. Qualitative observation shows that the microstructure of hot-dip galvanized TRIP steel is composed of ferrite, bainite, retained austenite and martensite, and martensitic transformation exists in the cooling process after the bainite transformation. The results of microstructure calculation show that the martensite carbon content in hot-dip galvanized TRIP steel is between 0.80% and 1.0% due to the influence of the isothermal transformation temperature of bainite. The longer the bainite isothermal time, The higher the carbon content of the martensite, the lower the Ms point. After the bainite transformation, some of the austenite with low carbon content undergo martensitic transformation during the subsequent cooling process, The existence of martensite fine structure of twin martensite, there is a small amount of dislocation martensite.