New Tungsten Borides, Their Stability and Outstanding Mechanical Properties

Area of Science:

• Materials Science
• Computational Materials Science
• Solid State Chemistry

Background:

• Tungsten borides are a class of inorganic compounds with potential applications in materials science.
• Predicting the stability and properties of novel materials is crucial for their development and application.

Purpose of the Study:

• To predict new tungsten boride compounds using computational methods.
• To evaluate the mechanical properties and thermodynamic stability of predicted tungsten borides.
• To investigate the temperature dependence of mechanical properties for boron-rich tungsten borides.

Main Methods:

• Composition-temperature phase diagram computation.
• Vickers hardness and fracture toughness calculations.
• Quasiharmonic and anharmonic approximations for temperature-dependent properties.

Main Results:

• Prediction of new tungsten borides, with WB5 identified as a superhard material.
• WB5 exhibits a predicted Vickers hardness of 45 GPa and fracture toughness of ~4 MPa·m^0.5.
• WB5 demonstrates thermodynamic stability across a wide temperature range at ambient pressure.
• Temperature-dependent mechanical properties of WB3 and WB5 were analyzed, indicating WB5 retains high performance at high temperatures.

Conclusions:

• Tungsten borides, particularly WB5, are promising candidates for superhard and high-performance materials.
• WB5 is predicted to be stable and maintain its mechanical integrity under various conditions, including high temperatures.
• Computational predictions provide a pathway for the experimental synthesis and application of novel tungsten borides.