Structural evolution of Fe33Zr67 and Fe90Zr10 metallic glasses

We report on the structural evolution of melt-spun Fe33Zr67 and Fe90Zr10 glasses. These glasses are subjected to isothermal annealing over a wide temperature range, varying from the onset of crystallization up to near the melting point, for 20-300 min. Over 733-1223 K, the phase evolution sequence of the Fe33Zr67 glass follows: fcc FeZr2 → fcc FeZr2 + bct FeZr2 → bct FeZr2. In contrast, annealing of the Fe90Zr10 glass over 903-1173 K leads to a mixture of α-Fe, Fe3Zr and Fe2Zr phases. Some Fe2Zr crystals are not developed perfectly, showing a special twin lamellar structure. The annealing temperature and alloy composition dependence of grain size in the present Fe-Zr system is discussed.