摘要
基于密度泛函理论的第一性原理方法,研究了Mg-Al-Ca-Si合金中主要强化相Al2Ca、Mg2Ca和Mg2Si的晶体结构稳定性、电子性质、弹性常数及声子性质,计算所得的晶格常数、实验数据与文献值吻合.合金形成热和结合能计算结果表明:Al2Ca具有最强的合金形成能力和稳定性.计算了Al2Ca、Mg2Ca和Mg2Si的体模量、剪切模量、杨氏模量和泊松比.结果表明:3 种二元相均为脆性相.通过电子态密度、Muliken电子占据数和金属性计算分析结构稳定性机制,表明共价键强弱顺序依次为Al2Ca、Mg2Si、Mg2Ca;声子性质表明Al2Ca、Mg2Ca和Mg2Si分别在 5.65、5.93 和 6.53 THz附近的晶格振动较强.
Abstract
Based on the first-principles method of density function theory,the crystal structure stability,electronic properties,elastic constants and phono properties of the main strengthening phase Mg2Si,Al2Ca and Mg2Ca in Mg-Al-Ca-Si alloy were studied.The calculated lattice constants are in good agreement with the experimental data and literature values.The calculation results of alloy forming energy and binding energy show that Al2Ca has the strongest alloy forming ability and stability.The bulk modulus,shear modulus,youngs modulus and poissons ratio of Al2Ca,Mg2Ca and Mg2Si were calculated.The results show that the three binary phases are brittle phases;the structural stability mechanism is analyzed by calculation of electron density of states,Mulliken electron occupation number and metallicity.It shows that the order of covalent bond strength is Al2Ca,Mg2Si and Mg2Ca.The phonon properties show that the lattice vibrations of Al2Ca,Mg2Ca and Mg2Si are strong near 5.65,5.93 and 6.53 THz,respectively.
基金项目
山西省高等学校科技创新项目(2021L385)
山西大同大学科研专项(云冈学研究)项目(2021YGZX34)
山西大同大学教学改革项目(XJG2020231)
山西大同大学博士科研启动基金(2019-B-05)
山西省科研启动基金(606-02010348)
NETL
NSTL
万方数据