Design Of Superhard Materials Research Articles

Computational prediction of ideal strength for a material

The ideal strength is crucial for predicting material behavior under extreme conditions, which can provide insights into material limits, guide design and engineer for enhanced performance and durability. In this work, we present a method within an allows for the estimation of tensile, shear, and indentation strengths in any crystallographic direction or plane. We have examined the strain-stress relationships of several well-known structures and compared our findings with previous work, demonstrating the effectiveness of our approach. Moreover, we performed extensive investigations into the indentation strength of hexagonal WC, β-SiC, and MgAl2O4. The current study uncovers the modes of structural deformation and the underlying atomistic mechanisms. The insights gained from this study have significant implications for the further exploration and design of superhard materials.

Generalized bond-strength model of Vickers hardness: Application to Cr4B, CrB, CrB2, CrB4, Mo2B, MoB2, OsB2, ReB2,WB2, WB3 and Ti1.87B50

The bond-strength model of Vickers hardness is generalized that can be utilized for any structure with covalent or polar-covalent bonds. We have applied the method to Cr4B, CrB, CrB2, CrB4, Mo2B, MoB2, OsB2, ReB2, WB2, WB3 and Ti1.87B50, and found the hardness of these borides to be within the range of 9–33GPa, in good agreement with experimental data. The generalization of the well-tried bond-strength model is inevitable for complex structures, opens up broader applications of its use and forms a practical tool for material scientists in the design of superhard materials.

Synthesis and Design of Superhard Materials

▪ Abstract The synthesis of the two currently used superhard materials, diamond and cubic boron nitride, is briefly described with indications of the factors influencing the quality of the crystals obtained. The physics of hardness is discussed and the importance of covalent bonding and fixed atomic positions in the crystal structure, which determine high hardness values, is outlined. The materials investigated to date are described and new potentially superhard materials are presented. No material that is thermodynamically stable under ambient conditions and composed of light (small) atoms will have a hardness greater than that of diamond. Materials with hardness values similar to that of cubic boron nitride (cBN) can be obtained. However, increasing the capabilities of the high-pressure devices could lead to the production of better quality cBN compacts without binders.