钢中贝氏体组织形态和亚结构(一)

Morphology and Substructure of Bainite in Steel(1)

研究贝氏体组织形貌和亚结构具有理论意义和工程应用价值。近年来应用TEM、SEM、STM、LSCM等设备观察研究了贝氏体的组织形貌和亚结构。研究表明贝氏体组织形貌和亚结构较为复杂,并随着转变温度的降低和碳含量的增加而演化。贝氏体组织中存在复杂的亚结构,存在亚片条、亚单元、较高密度的位错、精细孪晶等。贝氏体的组成相较多,除贝氏体铁素体基体外,还存在θ渗碳体、ε-Fe2.4C、残留奥氏体、马氏体等相。贝氏体组织中的碳化物只有θ渗碳体,ε-Fe2.4C,没有特殊碳化物。碳化物形状、大小、分布状态不同导致组织形貌多样。阐述了贝氏体组织形貌和亚结构的影响因素和形成机理。

It is of great significance in theory and application to study the morphology and substructure of bainite. The morphology and substructure of bainite were studied by transmission electron microscope, electronic microscope, sannning tunneling microscope and laser scanning confocal microscope in recent years. The results show that the morphology and substructure of bainite is complicated and will evolve with the decrease of the temperature and with the increase of the carbon content. Bainite has complex substruc- ture such as subslips, subunits, high-density dislocations and fine twins. The constituent phases in bainite are many kinds. Besides bainite ferrite, there are θ cementite, ε-Fe24C, retained austenite and martens- ite. The carbide in bainite are θ cementite and ε-Fe2.4 C without special carbide. The difference of the shape, size and distribution of bainite carbide result to the diversity of the morphology of bainite. The in- fluence factors and the formation mechanism of the morphology and substructure of bainite are expounded.