B2型钽钨有序合金的声子色散关系的研究  

STUDY OF PHONON DISPERSION RELATION FOR B2-TYBE TaW ORDERED ALLOY

作　　者：张晓军[1] 王安祥[1] 高宾[1] 凤飞龙[1] 

机构地区：[1]西安工程大学理学院,西安710048

出　　处：《低温物理学报》2015年第2期98-103,共6页Low Temperature Physical Letters

基　　金：陕西省教育厅科研计划项目(批准号:14JK1301);国家自然科学基金(批准号:11204227)资助的课题~~

摘　　要：应用改进分析型嵌入原子法模型和晶格动力学理论,计算了金属钽和钨以及B2型钽钨有序合金的原子力常数和动力学矩阵,模拟了金属钽和钨沿[ζ00]、[ζζ0]和[ζζζ]三个对称方向以及B2型钽钨有序合金沿[ζζ0]、[11ζ]、[ζζζ]和[ζ00]四个对称方向的声子色散曲线,并分析了B2型钽钨有序合金的振动特性.结果表明:金属钽和钨的声子色散曲线的模拟结果和实验值符合较好,特别在低频附近二者几乎一致;B2型钽钨有序合金中既有声频振动支又有光频振动支,光频支的振动频率均大于声频支的振动频率,且光频带和声频带之间由宽度约为0.82THz的空带隔开;在[ζζ0]对称方向上有六个独立振动模,在[11ζ]、[ζζζ]和[ζ00]对称方向上六个振动模均兼并为四个独立振动模,且各振动支的振动方向不尽相同.The atomic force constants and the dynamical matrix of metals Ta,W and B2-tybe TaW ordered alloy have been calculated,and the dispersion curves for bcc metals Ta and W along symmetry directions[ζ00],[ζζ0]and[ζζζ]and B2-tybe TaW ordered alloy along [ζζ0],[11ζ],[ζζζ]and [ζ00]symmetry directions respectively have been simulated by using the modified analytical embedded atom method and the theory of lattice dynamics.And then the vibration characteristics of the B2-tybe TaW ordered alloy have been analyzed.The results show that the simulated phonon dispersion curves of the bcc metals Ta and W are in generally agreement with the available experiment results,especial for lower frequency.There are both acoustic frequency branches and optical frequency branches observed in B2-tybe TaW ordered alloy,and the vibration frequencies of optical branches were greater than the acoustic branches.The optical frequency band and acoustic frequency band are separated by an empty band with width of 0.82 THz.There are six vibration modes along [ζζ0]directions,but four vibration branches in [11ζ],[ζζζ]and[ζ00]directions due to rotation symmetry,and the vibration directions of each vibration branches are in-completely identical.

关 键 词：有序合金 声子色散曲线 晶格动力学 改进分析型嵌入原子法 

分 类 号：TG146.41[一般工业技术—材料科学与工程]