摘要
通过超晶胞(SC)方法和虚拟晶体近似(VCA)方法的第一性原理计算,研究了金属二硼化物固溶体(Ti/Zr)_(1-x)(Ta/Nb)_(x)B_(2)(0≤x≤1)的形成能、混合能、晶格常数、体积、弹性常数、熔点、弹性模量、维氏硬度、断裂韧性和态密度。结果表明,二硼化物固溶体(Ti/Zr)_(1-x)(Ta/Nb)_(x)B_(2)的结构稳定性随掺杂浓度的增加而降低。Ti_(1-x)(Ta/Nb)_(x)B_(2)的体积随着掺杂浓度的增加而增加,这是因为Ta和Nb的原子半径大于Ti。而Zr_(1-x)(Ta/Nb)_(x)B_(2)的体积逐渐变小,这归因于Ta和Nb的原子半径比Zr小。并且,二硼化物固溶体(Ti/Zr)_(1-x)(Ta/Nb)_(x)B_(2)是力学性质稳定的脆性材料。特别地是,Ta和Nb的掺杂剂可明显改善固溶体(Ti/Zr)_(1-x)(Ta/Nb)_(x)B_(2)的脆性和体积模量以及断裂韧性,但硬度会降低。
First-principles calculations with supercell(SC)method and virtual crystal approximation(VCA)method were preformed to study the formation energy,mixing energy,lattice constant,volume,elastic constants,melting points,elastic modulus,Vickers hardness,fracture toughness and density of states of(Ti/Zr)_(1-x)(Ta/Nb)_(x)B_(2)(0≤x≤1)solid solutions.The formation energy results show that the structural stability of the diboride solid solution of(Ti/Zr)_(1-x)(Ta/Nb)_(x)B_(2) decreases with the increase of the concentration of doped atoms.The volume of Ti_(1-x)(Ta/Nb)_(x)B_(2) increases with the increase of the concentration of doped atoms,because the atomic radii of Ta and Nb are larger than that of Ti.While the volume of Zr_(1-x)(Ta/Nb)_(x)B_(2) becomes smaller,since the atomic radii of Ta and Nb are smaller than that of Zr.Moreover,the diboride solid solutions of(Ti/Zr)_(1-x)(Ta/Nb)_(x)B_(2) are mechanically stable and brittle materials.In particular,Ta and Nb dopants can significantly improve the brittleness,bulk modulus and fracture toughness of the solid solution(Ti/Zr)_(1-x)(Ta/Nb)_(x)B_(2),but reduce their Vickers hardness.
作者
刘长鸣
刘士余
刘彦昱
严达利
余浅
任海涛
于彬
李德军
Liu Changming;Liu Shiyu;Liu Yanyu;Yan Dali;Yu Qian;Ren Haitao;Yu Bin;Li Dejun(College of Physics and Materials Science,Tianjin Normal University,Tianjin 300387,China;Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University,Tianjin 300071,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2022年第10期3679-3688,共10页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51772209,11804023)。
关键词
第一性原理
金属二硼化物
结构稳定性
力学性能
first-principles
metal diborides
structural stability
mechanical properties
