镀铝层中的孪晶结构相与形成机制  

Twin microstructure phase and formation mechanisms of alumi-nized coating

作　　者：张伟[1] 庞碧君[2] 张金民[3] 

机构地区：[1]洛阳理工学院机电工程系,河南洛阳471023 [2]洛阳师范学院数学科学学院,河南洛阳471022 [3]洛阳船舶材料研究所电镜实验室,河南洛阳471039

出　　处：《焊接学报》2008年第12期49-52,共4页Transactions of The China Welding Institution

基　　金：河南省自然科学基金资助项目(082300440020);河南省科技计划项目(0624250037)

摘　　要：在20碳钢上制备了热浸镀镧铝涂层。经过850℃×4h的扩散处理后,采用透射电子显微镜研究了扩散层的组织结构。结果表明,扩散层中存在杆状和近似圆形状Al4C3相,且以孪晶方式存在。采用孪晶指数转换矩阵的方法,将转换矩阵作用于孪晶指数,得出Al4C3相是以(003)面为孪晶面,以[001]方向为旋转轴的180°二次旋转孪晶,其(003)面平行于杆的长轴方向,[001]方向垂直于杆的长轴方向,杆的长轴生长方向为[210]。从而证明了六方晶系中存在以(003)面为孪晶面,以[001]方向为旋转轴的180°二次旋转孪晶。分析了其形成机制。The La-aluminized coating on 20-carbon-steel was prepared by hot dip aluminizing method. The microstructure of Al4C3 phase in the coating was investigated through transmission electron microscope (TEM) after diffusion treatment at 850 ℃ for 4 h. The results indicate that the Al4C3 phases are rod-shaped and approximately sphericized, and the twinned Al4C3 phases exist in the coating. By using conversion matrix of twin index and the conversion matrix acting on twin index, it is proved that the Al4C3 phases are 180°secondary rotation twin with (003) as twinning plane and [001] direction as twinning axis. The long axis direction of rod-shaped Al4C3 phases is parallel to (003) plane and perpendicular to [001] direction, and its long axis direction is [210] direction. This shows that there is 180° secondary rotation twin with (003) as twinning plane and [001] direction as twinning axis in hexagonal system. The formation mechanism of the twinned Al4C3 phases is also discussed in the paper.

关 键 词：镀铝 扩散处理 孪晶 形成机制 

分 类 号：TG171[金属学及工艺—金属表面处理]