中文摘要：

采用基于第一性原理的赝势平面波方法系统地计算了Mg2Si弹性性质和热力学性质。根据计算数据得出Mg2Si在不同压强下的弹性常数，得出相对晶格常数（α／α0）、相对体积（V/V0）、体弹性模量与压强和温度的关系。通过准谐德拜模型计算了Mg2Si的热力学性质，如比热容和德拜温度，计算出的德拜温度与实验值基本相同。

英文摘要：

The elastic constants and some thermodynamic properties of Mg2 Si are calculated systematically by using the first-principles pseudopotential plane wave method. The elastic constants of Mg2 Si under different pressures are calculate＆ The dependences of the relative lattice parameters α/α0 on pressure P, the relative primitive volume V/V0 on pressure P, as well as the bulk modulus B with temperature and pressure are obtained successfully. The heat capacities and the Debye temperatures are calculated through quasi-harmonic Debye model. The calculated Debye temperature is equal to the experimental data.