高压下碳化钛热力学性质的第一性原理计算

碳化钛熔点高、硬度高、化学性能稳定性好,工业上主要用来制造金属陶瓷、耐热合金和硬质合金.采用平面波密度泛函理论广义梯度近似计算了碳化钛的弹性常数、晶格常数、体积模量,所得结果与实验和其它理论值相一致;通过准谐德拜模型预测了碳化钛的相对体积与压强,体积模量分别与压强和温度,热容与温度的变化关系,结果表明:温度对体积模量的影响远小于压强对体积模量的影响.该研究对碳化钛在高温高压下的应用具有指导意义.

Thermodynamic Properties of Cubic TiC under High Pressure from First-principles Calculation

Titanium carbide(TiC) is characterized as high melting point,high hardness and stable chemical properties,which is mainly used to make cermets and alloys in industry.The elastic and thermodynamic properties of Titanium carbide(TiC) are investigated by ab initio plane-wave pseudopotential density function theory method.The obtained lattice constant,elastic constants and bulk modulus B are consistent with the experimental and other theoretical calculation data.Through the quasi-harmonic Debye model,the dependence of the normalized volume V/V0 on pressure,the bulk modulus B on pressure P and temperature T,as well as the specific heat Cv on the temperature T are obtained also.We find that the effect of temperature on the bulk modulus is smaller than the pressure on the bulk modulus.The present result is useful for the application of TiC under high temperature and high pressure.