The effect of iron content on glass forming ability and thermal stability of Co-Fe-Ni-Ta-Nb-B-Si bulk metallic glass

Abstract

In this study, change in glass forming ability (GFA) and thermal stability of Co-Fe-based bulk metallic glasses were investigated as a function of iron content. Cylindrical samples of alloys with diameters of up to 4 mm were synthesized by a suction casting method in an arc furnace. Structures and thermal properties of the as-cast samples were determined by X-ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. It was found that the critical casting thickness of the alloys reduced as iron content was increased and cobalt content was decreased. It was determined that GFA parameters, reduced glass transition temperature (Tg/Tl) and δ (= Tx/(Tl − Tg)), show a very good correlation with critical casting thickness values. It was also observed that changing iron content did not effect thermal properties of the alloys.