The effects of temperature and pressure on the physical properties and stabilities of point defects and defect complexes in B1-ZrC

Abstract

With high stiffness, B1-ZrC in rocksalt structure is a hard structural material for various applications in harsh environments, whereas its tolerance of defects is elusive. Herein, we have investigated the stability and physical properties of B1-ZrC with point defects under high temperature and pressure by means of first-principles calculations accompanied with the quasi-harmonic Debye model. Our results illustrated that the introduction of point defects usually degrades the thermophysical properties. The formations of different point defects with the effects of temperature and pressure are characteristic and classifiable. The accumulation of point defects is in an orderly manner. Carbon vacancies and their complexes are the major point defects in population. The Gibbs energies of formation and concentrations of point defects are sensitive to pressure in the lower pressure range, suggesting an effective routine to manipulate point defects in ZrC. The nearest neighbor defect pair is the most stable at high pressure. The insights from our first-principles calculations might be helpful in material design and defects engineering for ZrC-based materials and its applications.