Electronic structure,bonding characteristics,and mechanical behaviors of a new family of Si-containing damage-tolerant MAB phases M_(5)SiB_(2)(M=IVB-VIB transition metals)

作     者：Na NI Hanchao ZHANG Yanchun ZHOU 

作者机构：School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Science and Technology on Advanced Functional Composite LaboratoryAerospace Research Institute of Materials&Processing TechnologyBeijing 100076China 

出 版 物：《Journal of Advanced Ceramics》 (先进陶瓷（英文）)

年 卷 期：2022年第11卷第10期

页      面：1626-1640页

核心收录：

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：financially supported by the National Natural Science Foundation of China(No.52072238) 

主　　题：borides MAB phases density functional theory(DFT) thermodynamic stability electronic structure mechanical properties 

摘      要：MAB phases are layered ternary compounds with alternative stacking of transition metal boride layers and group A element *** now,most of the investigated MAB phases are concentrated on compounds with Al as the A element *** this work,the family of M_(5)SiB_(2)(M=IVB-VIB transition metals)compounds with silicon as interlayers were investigated by density functional theory(DFT)methods as potential MAB phases for high-temperature *** from the known Mo5SiB2,the electronic structure,bonding characteristics,and mechanical behaviors were systematically investigated and *** the composition of M_(5)SiB_(2) does not follow the general formula of experimentally reported(MB)_(2z)A_(x)(MB_(2))_(y)(z=1,2;x=1,2;y=0,1,2),their layered structure and anisotropic bonding characteristics are similar to other known MAB phases,which justifies their classification as new members of this material *** a result of the higher bulk modulus and lower shear modulus,Mo_(5)SiB_(2) has a Pugh’s ratio of 0.53,which is much lower than the common MAB *** was found that the stability and mechanical properties of M_(5)SiB_(2) compounds depend on their valence electron concentrations(VECs),and an optimum VEC exists as the criteria for *** hypothesized Zr and Hf containing compounds,i.e.,Zr_(5)SiB_(2) and Hf_(5)SiB_(2),which are more interesting in terms of high-temperature oxidation/ablation resistance,were found to be unfortunately *** cope with this problem,a new stable solid solution(Zr_(0.6)Mo_(0.4))_(5)SiB_(2) was designed based on VEC tuning to demonstrate a promising approach for developing new MAB phases with desirable compositions.