Thermodynamic consideration of antiferromagnetic transition on fcc( γ)→hcp( ε) martensitic transformation in Fe–Mn–Si shape memory alloys

Abstract

On the basis of the empirical equations of Fe–Mn system and experimental information, T γ N and T ε N, Néel temperatures of fcc( γ) and hcp( ε) phases in Fe–Mn–Si shape memory alloys have been evaluated as follows: T γ N,FeMnSi=67 x Fe+540 x Mn[761+689( x Fe− x Mn)]−850 x Si; T ε N,FeMnSi=580 x Mn. Mn increases and Si decreases the Néel temperature of austenite. The antiferromagnetic transition influences the Gibbs energy of fcc( γ) and hcp( ε) phases in Fe–Mn–Si alloys. Therefore, addition of Si increases the driving force of martensitic transformation in Fe–Mn–Si alloy.