Zhang Tong, Yin Haiqing, Zhang Cong, Zhang Ruijie, Jiang Xue, Zheng Qingjun, Qu Xuanhui
Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China.
Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China.
Materials (Basel). 2019 Mar 22;12(6):967. doi: 10.3390/ma12060967.
For the purpose of exploring new hard materials and doping methods, the structural, mechanical and electronic properties of WCoB and W₂CoB₂ ternary boride were investigated with 0, 8.33, 16.67, 25 and 33.33 at.% V doping content and W₂CoB₂ with 0, 5, 10, 15 and 20 at.% V doping content by first-principle calculations. The cohesive energy, impurity formation energy and formation energy indicate the structural stability of V doped WCoB and W₂CoB₂. The elastic constants and mechanical properties imply that V doping leads to the decrement of shear modulus and the increment of ductility. Two different kinds of hardness models verify that V doping contributes to the decrement of hardness, which is closely related to shear modulus. The electronic structure is analyzed by DOS (density of states), PDOS (partial density of states) and charge density difference, which indicate the formation of weaker B⁻V covalent bonds, W⁻V and W⁻W metallic bonds lead to the decrement of mechanical properties. Compared with previous studies of Cr, Mn doped WCoB and W₂CoB₂, V doping leads to worse mechanical properties and hardness, indicating V may not be a suitable choice of doping transition elements.
为了探索新型硬质材料和掺杂方法，通过第一性原理计算研究了掺杂含量为0、8.33、16.67、25和33.33 at.%的V掺杂WCoB和掺杂含量为0、5、10、15和20 at.%的V掺杂W₂CoB₂的结构、力学和电子性能。结合能、杂质形成能和形成能表明了V掺杂WCoB和W₂CoB₂的结构稳定性。弹性常数和力学性能表明V掺杂导致剪切模量降低和延展性增加。两种不同的硬度模型验证了V掺杂导致硬度降低，这与剪切模量密切相关。通过态密度（DOS）、分态密度（PDOS）和电荷密度差分析了电子结构，结果表明较弱的B⁻V共价键的形成、W⁻V和W⁻W金属键导致力学性能下降。与先前关于Cr、Mn掺杂WCoB和W₂CoB₂的研究相比，V掺杂导致更差的力学性能和硬度，表明V可能不是掺杂过渡元素的合适选择。
