First-principles study of ceramic material (Ti_(1-x)Nb_x)_2AlC compounds and its compressive behavior under pressure up to 55 GPa

摘要

The structural, elastic, mechanical, electronic properties and its compressive behavior up to 55 GPa are studied for the (Ti_(1-x)Nb_x)_2AlC (x = 0,0.25,0.5,0.75,1.0) compounds using the first-principles calculation. Calculated structural parameters are in good agreement with experimental results, and all the considered (Ti_(1-x)Nb_x)_2AlC compounds are predicted to be elastically stable under 0-55 GPa pressure and are classified as brittle materials. Meanwhile, our study provides a metallic character of all the considered (Ti_(1-x)Nb_x)_2AlC compounds, and predicts them as promising good coating materials. Moreover, a significant increase (25.8%) in the bulk modulus is found with the Nb concentration changing from 0 to 1.0, and the reason is analyzed.