摘要
用 X 光、俄歇谱仪和透射电镜对低碳钢奥氏体氮碳共渗淬火及时效的化合物层成分和组织结构进行了研究。结果表明:化合物层灰区组织结构是ε-Fe_(2-3)(N,C)化合物基体上沉淀析出γ′(Fe_4N),γ′和ε之间取向关系:{0001}_e//{111)_γ′,〈11■0〉_e//〈011〉_γ′,γ′呈细片状沿{0001}_ε而析出,γ′之间具有180°旋转对称关系。初步探讨了氮、碳元素对共渗化合物层形成的影响及化合物层的强化机理。
The composition and microstructure of compound layer of the hardened austenitic nitrocarburised of low carbon steel qenched and aged have been examined by means of X-ray,AES and TEM.The experimental results show that the γ′-Fe_4 N precipitates from the ε-matrix in the grey zone of compound layer.The orientation relationship between γ′-phase and ε-matrix is determined as {0001}_ε∥{111}_(γ′),〈11■0〉_ε∥〈011〉_(γ′).The γ′-precipitates are appeared in thin plates lying on the{0001}_ε planes of ε-matrix and these γ′-plates are sometimes observed to be 180°related to each other.The influence of nitrogen and carbon contents on the formation of compound layer and the age-hardening mechanism are also discussed for austenitic nitrocarburising of low carbon steel.
关键词
奥氏体
化合物层
灰区
碳氮共渗
austenitic nitrocarburising (ANCT)
compound layer
grey zone
AES
TEM
