Magnetic Field Effect on α→γ Transformation of Fe-C Alloys by Differential Thermal Analysis under High Magnetic Fields

Abstract

The magnetic field effect on the α–γ transformation of hypoeutectoid steels (Fe-0.1wt.%C, Fe-0.23wt.%C, and Fe-0.47wt.%C) were investigated by differential thermal analysis under high magnetic fields B up to 26 T. The magnetic field effects for the transformation temperatures A₁ (αFe + Fe₃C → α-Fe + γ-Fe) and A₃ (α-Fe + γ-Fe → γ-Fe) were different from each other. The increment of A₁ induced by the magnetic field was independent from the carbon concentration. A₁ increased linearly for the magnetic field for B < 10 T, whereas A₁ increased quadratically for B > 20 T. A₃ for Fe-0.23 wt.%C increased quadratically against B. When the magnetic field of 26 T was applied, A₁ and A₃ for Fe-0.47wt.%C increased 35 K and 53 K, respectively. The magnetic field effects for the A₁ and A₃ are discussed on the basis of the gain of Zeeman energy for α-Fe.