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用透射电镜对钢的精细结构、碳化物的类型、形态、分布及残余奥氏体在基体中的分布进行了观察和鉴别。对钢的机械性能和马氏体亚结构间的关系也进行了研究。结果表明,板条马氏体内存在少量的微孪晶。碳化物往往沿此孪晶界优先析出,残余奥氏体在回火过程中的分解伴有碳原子的扩散。残余奥氏体分解产物之一是串状的渗碳体。板条间渗碳体和回火马氏体间的晶体学关系不符合关系。残余奥氏体的分解性质为上贝茵体反应。冲击韧性开始下降的温度和残余奥氏体开始分解的回火温度一致。残余奥氏体对裂纹扩展起延缓作用。
Transmission electron microscope (TEM) was used to observe the fine structure of steel, the type, shape and distribution of carbides and the distribution of retained austenite in the matrix. The relationship between the mechanical properties of steel and the martensite substructure has also been studied. The results show that a small amount of micro-twins exist in the lath martensite. Carbide is preferentially precipitated along the twin boundaries. The decomposition of residual austenite in the tempering process is accompanied by the diffusion of carbon atoms. One of the residual austenite decomposition products is a string-like cementite. Crystallographic relationships between lath cementite and tempered martensite do not correspond. Residual properties of retained austenite bivalve reaction. The temperature at which impact toughness begins to decrease is the same as the tempering temperature at which residual austenite begins to decompose. Retained austenite has a retarding effect on crack propagation.