Influences of multicenter bonding and interstitial elements on pseudo-twinned γ -TiAl crystal

Abstract The electronic properties of pseudo-twin boundary in γ -TiAl intermetallic and the influence of interstitial alloying atoms on them are investigated through ab initio calculation. Similar to true twin boundary, there exist three-central bonds at the pseudo-twin boundary, which are discussed by local energy scheme combined with electron localization function and quantum theory of atoms in molecules schemes. The effect of interstitial atoms C, N, H and O on slipping energy is separated into the contributions of affinity of interstitial atoms to host atoms and the multi-center bonds. In shearing process of pseudo-twin configuration, a local true twin boundary is formed in the neighbor layer of the initial pseudo-twin boundary, resulting in a plateau formed in stacking fault energy curve.