Tailoring Elastic, Mechanical, Thermophysical and Ultrasonic Properties of TMCs (TM= V, Nb, Ta)

Abstract

The elastic, mechanical, and thermoacoustic properties of transition metal carbides (VC, NbC, and TaC) were systematically
analyzed with respect to orientation and temperature. The second-third-and fourth-order elastic constants were determined using
the Coulomb and Born-Mayer potential model in the temperature regime 0–500 K. The analysis confirmed the elastic stability
of VC, NbC and TaC. Mechanical properties derived from the second-order elastic constants, reveals that VC, NbC, and TaC
exhibit brittle characteristics at room temperature. The thermal parameters, including Debye temperature, thermal conductivity
and thermal relaxation time were evaluated along the <100>, <110>, <111> orientations. The Debye velocity and Debye temperature were observed to reach maximum values along the <100> direction. The relaxation time due to thermal phonon process is of the order of intermetallics. Ultrasonic attenuation was predominantly governed by the Akhiezer mechanism rather than thermal relaxation effects. The calculated values were compared with other B1-structured materials, and the performance of VC, NbC, and TaC was assessed based on the obtained parameters.