Adjusting the balance between strength and ductile of the tetragonal TiAl3 alloy: a first-principles investigation

Abstract

ABSTRACT Although TiAl3 is widely used in various high-temperature fields, the adjustment of the balance between the strength and ductility of the tetragonal TiAl3 remains a challenge. To solve the key problem, here, we apply the first-principles method to study the influence of four transition metals (TM = V, Cr and Mo) on the mechanical properties of the tetragonal TiAl3. The structural stability of the TM-alloyed TiAl3 is examined by the impurity formation energy and phonon dispersion. The calculated results show that the TM-doped TiAl3 is stable at the ground state. In particular, the Mo-alloyed TiAl3 has better thermodynamic stability than the other TM-alloyed TiAl3. Importantly, the alloyed elements enhance the bulk modulus of TiAl3 because the alloyed elements improve the electronic hybridisation between the Ti atom and the Al atom. Here, the Mo-alloyed TiAl3 has the highest bulk modulus among the four TM-alloyed TiAl3. Furthermore, it is found that the alloyed elements improve the ductility of TiAl3.