No abstract

The electronic properties of Al-Ti intermetallics are receiving great attention in the specialized literature because these alloys present excellent mechanical performance at high temperatures. This consideration prompted our DFT-LDA and DFT-GGA ab initio study on electronic band structures, density of states, contour plots, Fermi Surface, Bulk modulus, and cohesive energy of intermetallics Al3Ti, AlTi, and AlTi3 using the FP-LAPW method. The band structure confirms their electrical conductivity, AlTi3 featuring a highly localized band associated to Ti 3d electrons around the Fermi level, not observed in the others. The DOS around the Fermi level is dominated by interactions between Al 3p and Ti 3d orbitals, whereas Al 3s and Ti 3d orbital interactions prevail in the regions of low and high energies, respectively. The density pseudogap in AlTi3 is located very close to the Fermi Level, granting a greater structural stability to this system. The Fermi Surface of these intermetallics, for which the authors found no previous reference in the literature, is reported. The difference in density distribution for the LDA and GGA methods is reflected in the contour plots. The Bulk modulus and cohesive energy values reported are in agreement with those reported in the literature.The study of the electronic properties of the AlTi system [12][13][14][15][16] has gained great acclaim thanks to the system's structural stability, reflected in its capacity for cohesiveness, its enthalpy of formation, and its mechanical properties [17][18][19][20][21][22][23][24][25][26][27]; all of which underscore the claim that ductility depends on the nature of the chemical bond. This ductility is associated to the directionality of the covalent bond between the Al 3p and the Ti 3d orbitals. Thus, by regulating this directionality, the fragility of these systems at low temperatures can also be regulated [28][29][30][31].Hong et al. [12] used the LMTO method to study the structural properties of Al 3 Ti for D0 22 , D0 19 , and L1 2 structures, obtaining results for the energies of formation, Bulk modulus, and phase stabilities of the three structures, the most stable phase corresponding to D0 22 . In addition, Hong et al. studied the AlTi 3 intermetallic [13] and, besides finding structural and electronic properties, they compared the bonding strengths of Al 3 Ti and AlTi 3 , to conclude that the Ti-Ti interactions of the latter influence the stability of the structure.Asta et al. [14] presented an ab initio study of the composition-temperature phase diagram of the Al-Ti system, and studied some structural properties of FCC structures, obtaining values for the formation energy, Bulk modulus, and atomic volume. Gutiérrez et al. [15,16] studied the charge density topology of Al 3 Ti, AlTi, and AlTi 3 , using the Dmol 3 program included in the computational package Material Studio, and were able to establish a relationship between topological density effects and macroscopic properties such as ductility. The compounds were systematically character...