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

• Using anisotropic elasticity calculations, we establish the twinning stress for Fe3Ga-B with various boron concentrations.
• The preference of boron over octahedral site to tetrahedral site was found by considering the total structural energy using DFT.
• We found that the stress level required for pseudotwinning increases with an increase in boron concentration.
• Remarkable elevation in twinning stress was observed when Fe3Ga was alloyed with 0.5 at.% boron.

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.