Exploring Physical Properties of Tantalum Carbide at High Pressure and Temperature

Abstract

Among the transition metal carbides, tantalum carbide (TaC) has gained significant interest due to its attractive mechanical and electronic properties. Here, we have performed high pressure and high temperature (HPHT) measurements on the physical properties of TaC under 5.5 GPa and rhythmically increased temperatures from 1000 to 1500 °C. The microscopic deviatoric strain, Vickers hardness, fracture toughness, grain size, and microstructures are characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and microhardness tests. The results reveal that the HPHT sintering causes the densification, which increases the mechanical properties of TaC. At 5.5 GPa and 1300 °C, the Vickers hardness, fracture toughness, relative density, and Young’s modulus of TaC are 21.0 GPa, 7.4 MPa m1/2, 457 GPa, and 97.7%, respectively, which are in good agreement with available experimental and theoretical values. It is found that the mechanical properties of TaC are highly impressible to the microstructures and microscopic deviatoric stress. Our cadent HPHT sintering technique will provide powerful guidance for further synthesis and design of other novel ultrahigh temperature ceramics (UHTCs).

Achieving Dislocation Strengthening in Hafnium Carbide through High Pressure and High Temperature

“…The results below demonstrate that our strategy is successful with HfC ceramics. On the one hand, the HPHT technique greatly reduces the sintering temperature of HfC; on the other hand, it also effectively improves the density of HfC by promoting the deformations of the crystal grains to produce a certain degree of defects, which is widely used in the synthesis of many refractory materials, such as diamond, cBN, and other transition metal carbides (ReB 2 , WC, and TaC). − In the present work, we consolidated a series of HfC ceramics by HPHT. The samples were characterized in terms of their density, microstructure, deformation behavior, mechanical properties, and oxidation resistance.…”