Phase stability, mechanical properties and lattice thermal conductivity of ceramic material (Nb1−xTix)4AlC3 solid solutions

Abstract

Using the first-principles calculation, we have studied the mechanical and thermal properties of the ceramic material Ti-alloyed Nb4AlC3 solid solutions. Calculated phase stability, elastic, mechanical properties indicate that all the (Nb1−xTix)4AlC3 (x increasing from 0 to 1.0 in a step of 0.125) solid solutions are thermodynamically, elastically stable and brittle materials. Moreover, lattice thermal conductivity and other related calculations predict these compounds have a relative high Debye temperature and melting point. This implies that the (Nb1−xTix)4AlC3 compounds possess a rather stiff lattice and good thermal conductivity. Particularly, the analysis of electronic structures and mechanical property calculations consistently indicate that the (Nb0.875Ti0.125)4AlC3 compound possess the highest hardness among the compounds considered. As expected, the mechanical properties of Nb4AlC3 can be improved to some extent by doping with Ti, in accordance with experiments.