Electronic and physical properties of Al3VxTi1−x (x=1, 0.875, and 0) alloys

Abstract

In this article, the electronic structure of Al3VxTi1−x (x=1, 0.875, and 0) alloys with and without planar faults has been investigated. The results for the bond order integral and interaction energy between atoms, the local density of states, and the energies of the planar faults (i.e., antiphase boundary and stacking fault) are presented for the alloys. The results show that the directional bonding of the p orbital of Al in the Al3V alloy leads to the brittleness of the alloy, whereas, in the Al3V0.875Ti0.125 alloy, the p orbital bonding characteristic of Al is partly weakened and the s orbital bonding characteristic of Al is partly increased. This may change the structure of the dislocation core. The results of the local density of states (LDOS) of the atoms on the planar faults in the alloys demonstrate that the planar faults make the peaks of the LDOS of Ti and Al on the planar faults shift toward higher energy regions, and thus may increase the structural energies of Ti and Al on the planar faults. With Ti partially replacing V in Al3V, the effect of the planar faults on the LDOS of Ti is weakened, which may decrease the energy of the planar faults. This is confirmed by the result of the energy of the planar faults for Al3VxTi1−x (x=1, 0.875, and 0) alloys. The result of the energies of the planar faults for Al3VxTi1−x (x=1, 0.875, and 0) also shows that the 〈111〉 directional stacking fault is stable in Al3Ti and that the 〈001〉 directional antiphase boundary is stable in Al3V. With Ti partially replacing V in Al3V, the energies of the planar faults decrease and the activity of deformation twining and type 〈110〉 superdislocation increase. This may provide more than five independent slip systems for the Al3V0.875Ti0.125 alloy and may improve the ductility of the Al3V alloy.