固态扩散条件下C在M_7C_3与M_(23)C_6碳化物转变中的作用

Main controlling element of M_7C_3 and M_(23)C_6 carbides transformation in solid state diffusion

对3Cr13不锈钢进行气体渗碳和高温脱碳处理,探究了M_7C_3型碳化物与M_(23)C_6型碳化物之间的转变关系,揭示了C在碳化物转变过程中起到的作用。结果表明:经过渗碳处理后不锈钢的组织中都出现了碳化物,碳化物的数量随着渗碳时间的延长而增加,而脱碳之后碳化物的数量明显减少。进行EDS分析后发现,不锈钢中存在一个特别的区域,在该区域两侧出现了碳含量差异很大,而铬含量几乎相同的碳化物。进行XRD剥离试验后发现,这个区域其实是M_7C_3与M_(23)C_6碳化物转变区,且脱碳之后该区域到渗碳表层的距离变小,说明在固态扩散条件下M_7C_3与M_(23)C_6碳化物之间的转变主要受碳含量的控制。

3Cr13 stainless steel was treated with the processes of gas carburizing and high temperature decarburizing.In order to explore the carbide transition relationship between M7C3 and M23C6,and reveal the main control element of carbide transformation.The results show that carbides appear in the stainless steel after carburizing,and the amount of carbides increases with the carburizing time,while the amount of carbides after decarburization is significantly reduced.Based on the EDS analysis results,it is found that there is a special region in the stainless steel,where carbides have a large difference in carbon amount and almost the same amount of chromium appeares on both sides.After XRD stripping test,it is found that this region is actually the transformation zone of M7C3 and M23C6 carbides,and the distance from the zone to the carburized surface after decarburization becomes smaller,indicating that the transformation between M7C3 and M23C6 carbides is mainly controlled by the carbon amount under solid state diffusion.