A systematic DFT study of (Ti3/2RE1/2)AlC alloys: A new database for adjustable mechanical and electronic properties

Abstract

In this study, ab initio calculations based on Pseudo-Potential Density Functional Theory (PP-DFT) method are carried out in order to highlight the partial substitution effect of Rare Earth (RE) elements in the well-known 211-MAX phase of Ti2AlC. The considered elements are Y, Sc and RE = La, Ce, Pr, Nd, Sm, Eu, Gd leading to (Ti3/2RE1/2)AlC alloys. According to the obtained results, the (Ti3/2RE1/2)AlC alloys are significantly less compressible under uniaxial stress along x and z axes. They exhibit high resistance to shearing along <001> direction. In addition, the calculated heat capacity for (Ti3/2RE1/2)AlC alloys increases with respect to the temperature, a maximum is found in the temperature range 200–300 K. Localized states occur in (Ti3/2RE1/2)AlC alloys due to the f states filling of the rare earth elements. The magnetic moment of (Ti3/2RE1/2)AlC compounds increases according to 4fn(n=2 for Ce to n=7 for Gd) filling. Our findings provide a theoretical database for new tunable properties of (Ti3/2RE1/2)AlC alloys.