Ti-Al金属间化合物结构与性质的第一性原理模拟

摘要/Abstract

摘要： 采用软件CASTEP模拟Ti-Al金属间化合物的晶体结构、力学性质和电子性质.分析在0 K、0 GPa时，Ti-Al存在的四种热力学稳定结构：TiAl₃、TiAl₂、TiAl、Ti₃Al，发现TiAl₃、TiAl₂、TiAl可以看作由Al的面心立方结构衍化而来，而Ti₃Al的结构与Ti相似，为密排六方结构.随着Ti摩尔分数的增加，TiAl₃、TiAl₂、TiAl、Ti₃Al的体模量相当，剪切模量和Vickers硬度逐渐减小；Pugh比k值也逐渐减小，表示韧性逐渐变好.最后对态密度、Mulliken布居分析等进行模拟，发现这四种结构Ti-Al键都具有金属性、共价性及弱的离子性.

关键词: Ti-Al金属间化合物, 力学性质, 电子性质, 第一性原理

Abstract: Crystal structure, mechanical and electronic properties of Ti-Al intermetallic compounds were studied using first-principles implemented in CASTEP. At 0 K, 0 GPa, thermodynamically stable structures are TiAl₃, TiAl₂, TiAl, Ti₃Al. Unit cells of TiAl₃, TiAl₂, TiAl are evolutions of face-centered cubic Al. Structure of Ti₃Al is similar to Ti, which is hexagonal close packing structure. Mechanical properties were calculated. It was found that with increasing of Ti molar fraction, their bulk modulus are approximate equivalent. But shear modulus and Vickers hardness decrease, and so did Pugh ratios. It shows that toughness became better. At last, density of state and Mulliken population analysis were simulated. Bonding nature of Ti-Al is a combination of metallic, covalent and weak ionic.

Key words: Ti-Al intermetallic compounds, mechanical properties, electronic properties, first-principles

中图分类号:

O641
O733

谭俊华, 朱开金, 彭军辉. Ti-Al金属间化合物结构与性质的第一性原理模拟[J]. 计算物理, 2017, 34(3): 365-373.

TAN Junhua, ZHU Kaijin, PENG Junhui. First-Principles Simulation on Structure-Property of Ti-Al Intermetallic Compounds[J]. CHINESE JOURNAL OF COMPUTATIONAL PHYSICS, 2017, 34(3): 365-373.

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