Mechanical and magnetic properties of new (Fe,Co,Ni)-B-Si-Ta bulk glassy alloys

The alloying effects of the like-atom substitution of Ni and Co for Fe on the various properties of Fe₇₀B_16.7-Si_8.3Ta₅ metallic glass are investigated in this present work. New Fe-based bulk glassy alloys, namely Fe_60-xCo_xNi_10-B16.7Si_8.3Ta₅ (at.%; x = 10, 20 and 30) with critical diameters up to 1.5 mm, were made by means of copper mold casting. A new glass-forming ability indicator, viz., the enthalpy of supercooled liquid, has been introduced for assessment of the glass-forming abilities (GFAs) of these Fe-based multi-component alloys. Nano-indentation results indicate that the calculated elastic modulus and hardness of the bulk glassy alloys are lower than those of the Fe₇₀B_16.7Si_8.3Ta₅ alloy. Among these bulk glassy alloys, Fe₇₀B_16.7Si_8.3Ta₅ exhibits the large elastic modulus and hardness with values of 178 ± 1 GPa and 12.9 ± 0.1 GPa, respectively. All the bulk glassy alloys exhibit good soft magnetic properties with high saturation magnetization B_s ~ 0.75-1.04 T but low coercive force H_c 0.2-5.2 A/m.