The influence of W-doping concentration on the structural stability, elastic properties, hardness, and
1Schools of New Energy and Materials, Southwest Petroleum University, Chengdu 610500, China. panyong10@swpu.edu.cn.
Abstract:
To improve the mechanical properties of ZrB2 ceramics, the influence of W-doping on the structural stability, elastic properties, hardness and brittle-to-ductile behavior of ZrB2 is studied using first-principles calculations. Three W-doping concentrations are considered. The results show that although W-doped ZrB2 exhibits both thermodynamic and dynamical stability, the structural stability of W-doped ZrB2 weakens with increasing W-doping concentration, particularly showing a reduction in dynamical stability. Furthermore, W-doping enhances the volume deformation resistance of ZrB2, while it reduces the shear deformation resistance and Vickers hardness of ZrB2. In particular, W-doping induces a trend of brittle-to-ductile transition in ZrB2 ceramics. Essentially, this improvement of the trend of brittle-to-ductile transition arises from the introduction of W-doping, which weakens the electronic interaction between B and B atoms along the shear direction. Therefore, we believe that the W metal is a promising element for improving the mechanical properties of ZrB2 high-temperature ceramics.
