Mo1-xWxC碳化物稳定性及力学性质的第一性原理计算
A first-principles study of the stability and mechanical properties of Mo1-xWxC carbides
周少兰 1丛大龙 1杨九州 1李立 1黄安畏 1冉旭东 1陈汉宾 1李忠盛1
作者信息
- 1. 西南技术工程研究所,重庆 400039
- 折叠
摘要
金属碳化物作为基体的增强相,对钢铁的力学性能起到至关重要的作用.采用基于密度泛函理论的第一性原理方法,通过虚拟晶体近似构建Mo1-xWxC(0≤X≤1)碳化物模型,计算Mo1-xWxC的晶格常数、形成能、结合能、弹性常数、弹性模量、泊松比u、维氏硬度、电子态密度等性质参数,分析W元素对MoC碳化物稳定性及力学性能的影响.本次计算值与其他理论计算值及试验值吻合度较高;随着W含量的增加,晶格常数增加,Mo1-xWxC的形成能、结合能皆为负值,结合能、形成能的绝对值均随着W含量的增加而增加.不同掺杂含量下的Mo1-xW,C均满足Born判据,在力学上是稳定的,随着W含量的增加,Mo1-x WxC的弹性常数、体模量、杨氏模量、剪切模量呈线性增加,B/G、泊松比降低.Mo1-xWxC在费米能级处的态密度值均不为0,态密度值随着W含量的增加而降低.Mo1-xWxC能自发形成且能稳定存在,随着W含量的增加,Mo1-xWxC碳化物的稳定性、弹性模量、硬度及耐磨性均增加,Mo1-xWxC呈脆性,脆性大小随着w含量的增加而增加.
Abstract
Metal carbides,as the reinforcing phase of the matrix,play a crucial role in the mechanical properties of steel.A first-principles approach based on density generalized theory is used to construct a Mo1-xWxC(0≤X ≤ 1)carbide model by virtual crystal approximation to calculate the property parameters,such as lattice con-stants,formation energy,binding energy,elastic constant,elastic modulus,Poisson's ratio u,Vickers hardness,and density of electronic states of Mo1-xWxC.The effects of W elements on the stability and mechanical proper-ties of MoC carbides were analyzed.The calculated values are in good agreement with other theoretical and ex-perimental values;the lattice constants increase with the increase of W content,the formation energy and binding energy of Mo1-xWxC are negative,and the absolute values of binding energy and formation energy increase with the increase of W content.The Mo1-xWxC with different doping contents satisfy the Born criterion and are me-chanically stable.the elastic constants,bulk modulus,Youngs modulus and shear modulus of Mo1-xWxC in-crease linearly with the increase of W content,and the B/G and Poisson's ratio decrease.The density of states values of Mo1-xWxC at the Fermi energy level are not zero,and the density of states values decrease with the in-crease of W content.Mo1-xWxC can form spontaneously and exists stably.The stability,elastic modulus,hard-ness and wear resistance of Mo1-xWxC carbides increase with the increase of W content,Mo1-xWxC is brittle,and the brittleness increases with the increase of w content.
关键词
第一性原理/虚拟晶体近似/Mo1-xW,C/力学性质Key words
First Principle/Virtual crystal approximation/Mo1-xWxC/Mechanical properties引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据