Structural, elastic, thermal and lattice dynamic properties of new 321 MAX phases

TL;DR

This study investigates the structural, elastic, thermal, and lattice dynamical properties of newly reported 321 MAX phases, revealing their stability, anisotropy, and potential for high-temperature applications.

Contribution

It provides the first comprehensive analysis of physical properties for the recently discovered 321 MAX phases, including stability, elasticity, and vibrational characteristics.

Findings

All phases are elastically anisotropic and brittle.

Debye temperatures and thermal conductivities are calculated.

Infrared and Raman modes are identified.

Abstract

A new series of MAX family designated as 321 phases are recently reported with Nb3As2C, V3As2C, Nb3P2C and Ta3P2C. Most of the physical properties of these new MAX phase compounds are unexplored and the present study aims to investigate their structural, elastic, thermal, and lattice dynamical properties. Their mechanical and dynamical stabilities are examined. All the phases are elastically anisotropic and brittle in nature. The Debye temperatures and lattice thermal conductivities have been calculated. Lattice dynamical features are investigated in detail and infrared and Raman modes are identified. High melting temperature of these compounds are favorable for their applications at elevated temperatures.