高压下TiAl_3结构及热动力学性质的第一性原理研究  

First-principles studies of the structural and thermodynamic properties of TiAl_3 under high pressure

作　　者：王海燕[1] 历长云[1] 高洁[1] 胡前库[1] 米国发[1] 

机构地区：[1]河南理工大学材料科学与工程学院,焦作454000

出　　处：《物理学报》2013年第6期443-448,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11147167;51202058;11104063);河南省教育厅自然科学研究计划项目(批准号:2011A140007);河南理工大学引进人才基金(批准号:Y2009-1)资助的课题~~

摘　　要：采用平面波赝势密度泛函理论研究了钛铝系金属间化合物TiAl3的结构性质,计算值与实验值及其他理论值相符合.通过准谐德拜模型研究了TiAl3的热动力学性质,计算得到了相对体积(V/V0)与压强和温度的关系,以及不同温度和压强下的热膨胀系数和热容.与TiAl的计算结果进行对比,发现随着温度的升高,TiAl的热膨胀系数增大的速度高于TiAl3,且随着压强的增大温度效应减弱;TiAl3的热容值近似为TiAl的热容值的2倍.In this paper, the structural properties of TiAl3 intermetallics are investigated by the plane-wave pseudopotential density functional theory method. The calculated results are consistent with experimental and other theoretical ones. Through the quasi-harmonic Debye model we calculate the thermodynamic properties and obtain the dependences of relative volume V/V0 on pressure P and temperture T, as well as the thermal expansion and specific heat coefficients under different temperatures and pressures. For the calculated results of TiAl, we find that the increase rate of thermal expansion coefficient of TiAl under the increase of temperature is higher than that of TiAl3, and further, the effect of temperature weakens with the increase of pressure. The specific heat of TiAl3 is nearly twice that of TiAl.

关 键 词：结构性质 热动力学性质 第一性原理 高压 

分 类 号：O469[理学—凝聚态物理]