Crystallization induced phase changes in amorphous Fe/sub 84/Nb/sub 7/B/sub 9/alloy

In the present investigations, a study of phase changes from amorphous to crystalline state was performed in an amorphous Fe/sub 84/Nb/sub 7/B/sub 9/ alloy with the help of in-situ electrical resistivity measurements in the temperature range 285-1200K during heating and 1050K to room temperature during cooling. The results were then confirmed with the help of X-ray diffraction (XRD) patterns recorded at room temperature after quenching the specimen from different temperatures after an appropriate heat treatment. It was observed that the first crystalline product appears at about 715K.The material was still amorphous and had crystalline phase such as hexa-FeNb and Fe/sub 2/Nb up to temperature of 825K. A new crystalline phase hexa-B appeared around 873K hexagonal phase disappeared and instead of it alpha-Fe (b.c.c.) phase. Above 973K, compounds like FeB (orthorhombic) and Nb/sub 3/B/sub 3/ (tetragonal) were also indexed in the alpha-Fe (b.c.c.). The results were found in good agreement with those of different scanning calorimetry (DSC) and transmission electron microscopy (TEM) as reported in the literature. (author)