V和VI族过渡金属共掺杂对四硼化钨力学性能影响机制的理论研究

项目名称： V和VI族过渡金属共掺杂对四硼化钨力学性能影响机制的理论研究

项目编号： No.11304140

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 李晓凤

作者单位： 洛阳师范学院

项目金额： 25万元

中文摘要： 四硼化钨(WB4)是过渡金属硼化物中硬度最高的，在工业方面具有广泛的应用引起了大家的关注。在WB4中掺杂其他过渡金属能够改善其硬度和力学性能，是目前科学研究的热点问题。本项目拟采用粒子群优化算法结合第一性原理的方法研究过渡金属掺杂对WB4的力学性能和硬度影响的物理本质。首先利用晶体结构预测方法确定WB4高压结构，得到其弹性性质，硬度以及热力学性质等。在此基础上，研究单掺杂和共掺杂V（Nb、Ta）族和VI (Cr、Mo)族对WB4力学性质、硬度以及电子结构的影响。根据过渡金属掺杂后WB4硬度及力学性能的变化，从而来探索过渡金属掺杂对WB4性质影响的内在物理机制。本项目的研究将为现有超硬材料的改进，新型超硬材料的筛选、设计、优化等提供先期的理论预测和科学依据。

中文关键词： 四鹏化钨；晶体结构预测；力学性能；硬度；掺杂

英文摘要： WB4 is hardest in all transition metal borides, the application in industry has been got a lot of publicity. Therefore, whether doping transition metal can improve the hardness and mechanical properties of WB4 has been a hot problem of scientific research. In this project, the partical swarm optimization and the first-principles method will be combined to study the effect mechanisms of the hardness and mechanical behavior of WB4 after doping transition metal in WB4. Firstly, the high crystal structure of WB4 is refined, the elastic constants, hardness and thermodynamic are calculated. After that, we study the influence of the same main group transition metal (V (Nb, Ta) and VI (Cr, Mo)) doping and codoping on the mechanical properties, hardness and electronic structure. According to variation of hardness and mechanical properties of WB4 after doping and codoping, we can obtian the influence mechanism of transiton metal element doping and codoping on the mechanical properties and hardness of WB4 system. This study will provide the designer with information with which he can tailor superhard materials. Such predictive capabilities also provide the early theoretical prediction and scientific basis for the screen, design and optimization of novel superhard materials.

英文关键词： WB4；crystal structure prediction；mechanical properties；hardness；doping