Influence of antiphase boundary period parameter M′ on elastic and electronic properties of one dimensional long period structures of Al3Ti

► With increase of M′, elastic constant C11 decreases, whereas C12, C44, C66 increase. ► Elastic moduli G and E also increase. ► Ga increases while Gc/Ga decreases and oppositely, Ea decreases while Ec/Ea increases. ► Elastic anisotropy of two-dimensional directional dependencies of G and E enlarges. ► Metallic bonding is weakened while covalent bonding is enhanced.