<title>Mesostructure of Fe-based ribbon influenced by inner stress</title>

Abstract

The mesostructure of Fe-based (Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 ) nanocrystalline ribbon was observed by investigation of the section samples and the molted samples with atomic force microscopy (AFM). The section of the Fe-based crystalline ribbon can be divided into five areas. An apparent mesostructural difference was found in the different areas of the ribbon crystallized after annealing. In RFA, the coarse grains gathering in longitudinal arrangement, while in FFA the fine grains gathering arranged transversely dominates. The size of crystalline grain increases from about 10 nm to about 300 nm with the area gradating from the free surface to the rolled surface. The main reason for such mesostructural difference could be due to the different residual inner stress in the different areas of the amorphous ribbon.