Tailoring the structure, mechanical, electronic, and thermodynamic properties of Al8Mn5 by doping Ti atom with different atomic site configurations

Abstract

To solve the problem of the influence of Ti particles on Al8Mn5 phases is difficult to observe from the experiments, the effects of Al8Mn5 doped with Ti atom at different Wyckoff sites on its thermodynamic properties, mechanical properties, and electronic structural characteristics were systemically studied by first-principles calculations in this work. It was found that the doping of Ti can enhance the thermodynamic, dynamic, and mechanical stability, change the elastic anisotropy in different directions, and decrease the ductility of Al8Mn5. The calculated mechanical results showed that the bulk modulus decreased, while the Young's modulus (E), hardness (HV), and shear modulus improved for the Ti-doped Al8Mn5 phases. The Al–Ti5 phase in Ti doping Al sites and the Mn–Ti3 phase in Ti doping Mn sites have the largest E with the values of 234.59 and 233.25 GPa, respectively. Additionally, the Al–Ti5 and the Mn–Ti3 phases have the highest HV of 16.24 and 16.06 GPa in Chen's model, and 14.31 and 14.48 GPa in Tian's model, respectively. The electronic structures and chemical bonding characteristic information elaborated that the improvement in mechanical properties is due to the improvement in Al–Mn and Al–Al bond strength.