Ab initio study of phase stability,elastic anisotropy,and minimum thermal conductivity of MnB_(2) in different crystal structures  

作　　者：Xiao-Fan Wang Yi-Xian Wang Zhuo Wang Yu-Xuan Zhang Jian-Bing Gu 王小凡;王乙先;王卓;张宇轩;顾建兵(College of Science,Xi'an University of Science and Technology,Xi'an 710054,China;School of Materials and Chemical Engineering,Zhongyuan University of Technology,Zhengzhou 450007,China)

机构地区：[1]College of Science,Xi'an University of Science and Technology,Xi'an 710054,China [2]School of Materials and Chemical Engineering,Zhongyuan University of Technology,Zhengzhou 450007,China

出　　处：《Chinese Physics B》2024年第12期367-375,共9页中国物理B（英文版）

基　　金：Project supported by the Natural Science Basic Research Program of Shaanxi Province,China(Grant No.2024JCYBQN-0044);the National Natural Science Foundation of China(Grant No.11904282);the Doctoral Scientific Research Foundation of Xi’an University of Science and Technology(Grant No.2018QDJ029)。

摘　　要：The phase stability,elastic anisotropy,and minimum thermal conductivity of MnB_(2) in different crystal structures have been investigated by first-principles calculations based on density functional theory.The results found that P6_(3)/mmc(hP6-MnB_(2)),P6/mmm(hP3-MnB_(2)),Pmmn(oP6-MnB_(2)),R■m(hR3-MnB_(2)),Pnma(oP12-MnB_(2)),and Immm(oI18-MnB_(2))all exhibit mechanical and dynamic stability under environmental conditions,and the sequence of phase stability was hP6>hR3>oP6>0I18>oP 12>hP3.In addition,Vickers hardness calculations indicated that hP6,hR3,oP6,and oI18of MnB_(2)have potential as hard materials,while hP3 and oP12 are not suitable as hard materials.Moreover,the elastic anisotropy of different MnB_(2)phases were also comprehensively investigated.It is found that the anisotropic order of bulk modulus is oP12>hP3>hP6>hR3>oI18>oP6,while that of Young's modulus is oP12>hR3>hP6>oP6>hP3>oI18.Furthermore,the minimum thermal conductivity of different MnB_(2)phases was evaluated by means of Clarke's and Cahill's models.The results suggested that these MnB_(2) diborides are all not suitable as thermal barrier coating materials.

关 键 词：transition metal boride mechanical properties density functional theory 

分 类 号：O469[理学—凝聚态物理]