Uniaxial loading response of one dimensional long period structures of Al3Ti

First-principles calculations have been performed to systematically investigate the uniaxial loading response of seven one dimensional long period structures Al3Ti. The stress–strain relations under [1 0 0] and [0 0 1] uniaxial tensile deformation reveal that the distinction of Ea and Ec increases as increase of antiphase boundary period parameter M′. Both of the Young modulus and the lattice parameters variation indicate that the inter-atomic interactions along [0 0 1] direction is much stronger for all of these structures. The peak tensile stresses show that, except for 〈3 2〉, the [1 0 0] direction uniaxial tensile deformation is much easier. Furthermore, it is interesting to find that the critical tensile strains under [1 0 0] direction decrease with increase of M′, meaning the existence of antiphase boundary reduces the symmetry of the crystal and leads to poor ductility. Electronic structures development indicate that with increase of the strain the electron density exhibits gradual depletion together with stretch of bonds and the structure gradually becomes unstable.