不同退火温度下铁基薄带介观结构的AFM研究

用原子力显微镜(AFM)观测了铁基合金(Fe73.5Cu1Nb3Si13.5B9)薄带断口的介观结构.通过对310℃退火样品的观测,可以发现薄带的贴辊面区(SRFA)和自由面区(FFA)存在着非常明显的结构差异;而540℃退火样品的AFM观测结果则显示这种差异并不明显.将310℃和540℃退火的样品在HF酸溶液中进行腐蚀,获得不同腐蚀深度的腐蚀表面,再用AFM观测其表面形貌,则发现:在310℃退火样品的腐蚀表面,自由面和贴辊面形貌各自随腐蚀深度的变化而变化,并且两表面形貌之间在腐蚀前期有差异,但后期无明显不同;而540℃退火样品的两个腐蚀表面,则不存在这样的变化和差异.该观测结果与薄带断口观测到的介观结构相符合.造成这种结构差异的原因是经不同温度退火后,薄带内部残留的内应力不同.

AFM Investigation of Mesostructure of Fe-based Ribbons Annealed at Different Temperatures

The mesostructure at the cross section of Fe-based alloy ribbon ( Fe73.5 Cu1 Nb3 Si13.5 B9 ) was observed with atomic force microscopy (AFM). It is found that there is an apparent structural difference between the sticking roller face area (SRFA) and the free face area (FFA) of the ribbon annealed at 310℃, and a structural conformity of the ribbon annealed at 540℃ . In this paper, the free surface and the sticking roller surface of the ribbons after corrosion in HF solution at different corrosive depths were observed by AFM. The result shows that, for the specimen annealed at 310℃, there are some topographic differences between the two etched surfaces which are apparent at the early period and unapparent at the later period of corrosion, besides the topography of them is changing with the increase of corrosive depth. While for the specimen annealed at 540℃, there are no obvious structural change and differences. This result is consistent with the observation at the ribbon' s cross section, and this structural difference is caused by the different residual stress remained in the ribbon annealed at different temperatures.