压力诱导的四方相立方氮化硼的结构、弹性、本征硬度和理想强度

Pressure-induced structure, elasticity, intrinsic hardness and ideal strength of tetragonal CN.

作者信息

Shi Zhijun, Shao Wei, Rao Lixiang, Xing Xiaolei, Zhou Yefei, Ren Xuejun, Yang Qingxiang

机构信息

State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao 066004, P. R. China.

State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, P. R. China.

出版信息

Phys Chem Chem Phys. 2022 Feb 23;24(8):5171-5184. doi: 10.1039/d1cp05163f.

DOI:10.1039/d1cp05163f

PMID:35166285

Abstract

A tetragonal CN (t-CN) structure was predicted CALYPSO code, and the effects of pressure on its structural and mechanical properties were studied. The results show that t-CN is different from various 2D CN compounds with a new type 3D crystal structure, which is similar to diamond. Bulk t-CN is equipped with excellent elastic properties. When the pressure is increased from 0 GPa to 350 GPa, its bulk modulus , shear modulus and Young's modulus are increased from 426.9 GPa to 1123.1 GPa, 371.4 GPa to 582.9 GPa and 863.7 GPa to 1490.9 GPa, respectively. The anisotropic , and are increased from 582.38 GPa to 1751.41 GPa, 478.29 GPa to 1033.97 GPa and 1281.26 GPa to 2490.14 GPa, respectively. When the pressure is 0 GPa, the hardness calculated by Chen's and Tian's models are 51.15 GPa and 51.81 GPa, respectively. Its ideal tensile strength in [111] orientation is the smallest (63.46 GPa), which indicates that the (111) planes allow easy cleavage. The smallest ideal shear strength (67.98 GPa) can be obtained in the (111)[11̄0] orientation, which suggests its theoretical hardness is about 67.98 GPa. Due to its excellent mechanical properties, t-CN can be used as an industrial superhard material.

摘要

利用CALYPSO程序预测了一种四方相的类金刚石结构（t-CN），并研究了压力对其结构和力学性能的影响。结果表明，t-CN具有不同于各种二维类金刚石化合物的新型三维晶体结构，与金刚石相似。块状t-CN具有优异的弹性性能。当压力从0 GPa增加到350 GPa时，其体模量、剪切模量和杨氏模量分别从426.9 GPa增加到1123.1 GPa、从371.4 GPa增加到582.9 GPa、从863.7 GPa增加到1490.9 GPa。各向异性的、和分别从582.38 GPa增加到1751.41 GPa、从478.29 GPa增加到1033.97 GPa、从1281.26 GPa增加到2490.14 GPa。当压力为0 GPa时，根据陈模型和田模型计算得到的硬度分别为51.15 GPa和5,181 GPa。其在[111]方向上的理想拉伸强度最小（63.46 GPa），这表明（111）面易于解理。在（111）[11̄0]方向上可获得最小的理想剪切强度（67.98 GPa），这表明其理论硬度约为67.98 GPa。由于其优异的力学性能，t-CN可作为一种工业超硬材料。