摘要
基于第一性原理方法计算Ti-25%Nb(原子分数,下同)合金三种相结构(β、α″和ω相)的弹性常数、态密度、电荷密度和Mulliken布居,在此基础上探究Ti-25%Nb合金的力学性能、键合特征及二者内在联系。计算结果表明:α″相的生成可以抑制β向ω相的转变;β、α″和ω相的主要成键类型为金属键,其次还包括共价键和离子键;β相的金属键和离子键强度最高,α″相的共价键强度最高;三种相结构的力学性能主要取决于金属键强度,金属键的增多有利于合金弹性模量的降低;单位原子d电子态密度在费米能级处的数值越高,所对应的晶体结构杨氏模量越小。金属键可以提高延展性,抑制脆性,削弱成键的定向强度,从而降低合金相的强度。本研究揭示了Ti-25%Nb合金在β→α″、ω亚稳相转变过程中力学性能的变化和键合特征,可为β钛合金的制备和力学性能分析提供一定的理论依据。
Based on the first-principles method,the elastic constants,density of states,charge density,and Mulliken population of three phase structures(β,α″andωphases)of Ti-25at%Nb alloy were calculated.On this basis,the mechanical properties,bonding characteristics and internal relations of Ti-25at%Nb alloy were explored.The results showed that the formation ofα″phase can inhibit the phase transformation ofβ→ω.The main bonding types ofβ,α″andωphases are metal bonds,followed by covalent bonds and ionic bonds.The strengths of metal bond and ionic bond inβphase are the highest,and the covalent bond strength of theα″phase is the highest.The mechanical properties of the three phase structures mainly depend on the strength of the metal bond.The increase of metal bonds is beneficial to the decrease of the elastic modulus.A higher d-electron density of states per atom at Fermi level corresponds to a lower Young’s modulus of the crystal structure.Metal bonds can improve ductility,inhibit brittleness,and lower the directional strength of bonds,thereby reducing the strength of the alloy phase.This study provides a theoretical basis for the preparation and mechanical properties analysis ofβ-type titanium alloys.
作者
陈怀昊
刘海博
邓林红
CHEN Huaihao;LIU Haibo;DENG Linhong(School of Intelligent Manufacturing,Shazhou Professional Institute of Technology,Zhangjiagang 215600,Jiangsu,China;School of Materials Science&Engineering,Changzhou University,Changzhou 213164,Jiangsu,China;School of Earth Science,Zhejiang University,Hangzhou 310058,China;School of Medical and Health Engineering,Changzhou University,Changzhou 213164,Jiangsu,China)
出处
《材料导报》
北大核心
2025年第15期260-267,共8页
Materials Reports
基金
国家自然科学基金(31670950)
江苏高校‘青蓝工程’。
