Kinetics of σ-phase formation in equiatomic cold-rolled Fe–V alloys

• Kinetics of alpha-to-sigma phase formation in Fe–V alloys.
• Activation energy for the sigma-phase formation.
• B2 ordered phase is a precursor of the sigma-phase.

The kinetics of α-to-σ phase transformation in equiatomic Fe–V cold-rolled alloys was studied by the Mössbauer spectroscopy (MS) and X-ray diffraction (XRD) techniques. The kinetics could be well-described in terms of the Johnson–Mehl–Avrami–Kolmogorov type equation. The activation energy has been determined as being 189 kJ mol−1 and the Avrami exponent as close to 3. The σ-phase precipitation rate was found to be the highest at 800 °C. Prior to the formation of the σ-phase the ordered B2 phase was revealed, as a precursor of σ, by both MS and XRD techniques.