中文摘要：

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.

英文摘要：

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.