Crystallization and soft magnetic properties of metalloid-free Fe89Hf7Al3Zr1 amorphous alloy

A new high iron content metalloid-free Fe-based amorphous alloy with the nominal composition of Fe89Hf7Al3Zr1 was fabricated by melt-spinning technique. The alloy shows good soft magnetic properties, such as saturation induction Bs up to 1.60 T and coercivity Hc as low as 4.3 A/m. Crystallization was investigated in non-isothermal conditions using DSC measurements. It was shown that the observed DSC peaks may be attributed to precipitation of α-Fe phase and Fe2Hf(Zr) compound, respectively. The apparent activation enthalpy Ep of both the exothermic peaks was determined by Kissinger and Ozawa models. The local activation enthalpy E(x) decreases gradually with crystallized volume fraction x indicating that crystallization process of the second step becomes easier. After annealing at different temperatures, the Bs maintains a trend of increase in each crystallization process. The optimized annealing process is established at 798 K (close to Tp1) for 0.5 h with maximum Bs of 1.75(± 0.01) T.