Pseudoelasticity in Fe₃Ga with boron-A combined atomistic-micromechanical treatment

Abstract The Fe₃Ga base alloy is known to exhibit pseudoelasticity and the solute hardened Fe₃GaB holds considerable promise as well. The present work aims at developing a theoretical model to establish the critical twinning stress in Fe₃Ga with varying boron concentration. The theoretical model is based on the atomistic-micromechanical approach where we utilize density functional theory and Peierls Nabarro formalism at an atomic scale and the Eshelbian anisotropic elasticity at microscale. Using local strain measurements at the grain scale, we also show the experimental evidence of effect of boron in elevating the twinning stress in Fe₃Ga. The work calculates the interaction energies associated with the presence of boron in octahedral, tetrahedral and xenohedral sites in the D0₃ lattice and the transition from octahedral to xenohedral sites upon twinning. The model distinguishes the elevation of twinning stress depending on the interstitial site and the transition between the sites.