Structural investigation of Fe(Cu)ZrB amorphous alloy

The crystallization process in Fe-86(Cu-1)Zr7B6 and Fe87Zr7B6 is investigated using the methods of transmission electron microscopy, electron and X-ray diffraction and resistrometry. Two crystallization reactions take place during thermal annealing of amorphous Fe-86(Cu-1)Zr7B6 and Fe87Zr7B6 alloys. In both alloys the first crystallization begins with the formation of nanocrystalline alpha-Fe at temperature to approximately 800 K. The second crystallization starts above 1000 K; the nanocrystalline phase dissolves and together with the remaining amorphous matrix form rough grains of alpha-Fe and dispersed Fe23Zr6 phases. From Mossbauer spectroscopy it seems that there exist two neighbourhoods of Fe atoms in the amorphous structure. One of them is characterized by low Zr content and is responsible for the high-field component of the hyperfine held distribution p(H). The second one is rich in Zr and B and is responsible for the low-held component of p(H). This is in accord with the observation of two crystallization steps separated by a large interval of temperatures due to the existence of two chemically different regions or clusters.