镀铁离子氮碳共渗层中γ’和ε相的电镜研究

TEM Study of γ' and ε Phase in Ion Nitrocarburized Iron Plating Layer

用透射电镜对镀铁离子氮碳共渗层中γ’相和ε相进行了研究,发现化合物层中ε相可以在γ’相不同的门{11H}γ’上形成,两相之间取向关系仍旧是{0001}ε//{111}γ’,<(?)110>//<1(?)0>γ’,不同{111}γ’ 面上形成的ε相变体之间以[1OO]γ’,或[110]γ’,为轴旋转孪晶关系.形态上与ε相中片层状γ’孪晶明显不同.扩散层中形成的针状γ’相内存在许多无规的层错.这些层错的有序排列可以形成不同的多型体,现已发现.L=6和L=7的两种γ’相多型体.

γ' and e phase in ion nitrocarburized iron coating have been studied with TEM. It has been found that the transformation from γ' to ε phase in the compound layer can be realized through a change of the arrangement order of the closely packed planes in γ' phase, while the orientation relationship between γ' and e phase still is {0001}ε // {111}γ'/{(?)110>ε//<1(?)0>γ' and the varieties of e phase on the different {111 }γ' planes have the 180?rotating twin rela-tion with 001 or 110 as the axis. There exist a lot of random stacking faults in the rod-like γ' phase forming during the cooling of the diffusion layer and the ordering of the stacking faults leads to the formation of variant polytypes of γ' phase, in which two kind of poly types have been found.