Nanocrystallization and fracture characteristics in Co-based ribbons

The fracture characteristics, Young's modulus and Vickers hardness of nanocrystalline materials obtained from the amorphous precursor Co66Fe4Mo2Si16B12 by thermal treatments at two different temperatures (slightly and well below the crystallization temperature) have been studied. The results show that these nanocrystalline materials are very brittle and the plastic flow involved in the fracture process practically disappears in the case of the material obtained at the temperature slightly below the crystallization one. In addition, an interesting nanolamellar structure has been observed in this sample.