First-principles studies of typical long-period superstructures Al5Ti3, h-Al2Ti and r-Al2Ti in Al-rich TiAl alloys

▸ The present investigation presents detailed information on mechanical properties of Al5Ti3, h-Al2Ti and r-Al2Ti Al-rich LPSs such as elastic anisotropy, ductility and brittleness. ▸ The electronic structures indicate strong directional bonding between Ti and Al atoms due to strong hybridization between them. ▸ The calculated formation enthalpies show that r-Al2Ti is most stable from energetic point of view, and then followed by h-Al2Ti, Al5Ti3 and γ-TiAl.