渗铝钢中的调幅分解及其形成原因

Spinodal Decomposition Structures in Diffusion Layer of Aluminized Steel and Its Formation Mechanism

利用透射电子显微镜研究了经850℃×4h扩散后热浸镀铝层的微观组织。结果表明,在扩散层的Fe2Al5和FeAl2相上存在调幅分解。从扩散层表面向内部,调幅组织形貌从平行直线状向平行交叉条纹状再到网格状过渡。在扩散层的部分区域,晶界对调幅分解形貌有明显的影响。各晶粒内部有各自的调幅分解组织;在整个晶粒内,调幅分解条纹呈片层状。分析了调幅组织的形成原因。

Microstructure and composition of diffusion layer of the hot dip aluminized steel after diffusion at 850 ℃ for 4 hours were investigated by TEM (transmission electron microscope). The results show that spinodal decomposition phenomenon is observed in Fe2Al5 and FeAl2 phases in diffusion layer. The pattern of spinodal decomposition structure is involved from parallel beeline to parallel across striation and then to lattice shape from the surface to inner of diffusion layer. There exist obvious effects of grain boundary on spinodal decomposition structure in some area of diffusion layer. In addition, there exist different spinodal decomposition structures in every grain. The stripes of the spinodal decomposition structure exhibit lamellar structure in inner in whole crystal. The formation mechanism of the spinodal decomposition structure was described based on the 15% rule.