Study of FeNi-L10 ordering via quasi equilibrium cooling process

Two Fe–Ni alloys were prepared using the arc melting method: Fe50Ni50 and Fe64Ni36. The samples after annealing were reheated up to 650°C and cooled at a very slow rate to approach thermodynamic equilibrium. The coarse grains of the as prepared samples have been substantially reduced after thermal process resulting in a larger fraction of grain boundaries and a higher diffusivity. Magnetic hysteresis curves reveal an increased coercivity of the cooling processed samples compared to the annealed samples. These results suggest that during slow rate cooling a partial phase transition of disordered γ-FeNi to ordered L10 is possible to occur.