Evaluating Volume Thermal Expansion Coefficient Of Solid At Different Temperature Based On Measured Date Of Isothermal EOS

In solid physics,the Griineisen Law that based on the Debye Model is a kind of common and effective method to calculate the thermal expansion coefficient of solid.However,using the method to calculate the thermal expansion coefficient of solid needs a number of material physical parameters.The bulk modulus of solid material at different temperature in particular is difficult to determine,and the data in previous studies is very limited.Aiming to solve this problem,this paper gives a mechanic-hot effects equivalence postulate,which suggests the similarity of the influence on the bulk modulus between temperature of solid and the compression process of solid.Therefore the volume can be taken as a bridge,and the bulk modulus at temperature T(zero pressure)can be replaced by the bulk modulus at pressure P(room temperature)in calculation.By fitting the measured data of the solid constitutive behavior of pressure P and the volume V in the condition of isothermal,the solid isothermal equation of state P(V)was obtained,and then the bulk modulus B(V)at different pressure was determined,as well as the bulk modulus B at different temperature.Taking physical parameters of 15 kinds solids at room temperature(300K)as initial values,after step by step calculating,we can obtain volume thermal expansion coefficients of 15 kinds solids such as Ag,Al,Au etc.at each temperature.The temperature ranges from OK to about 1000K(for several metals,the temperature range exceeds 2000K).On the other hand,Yeping Eqution was intrudced for calculating the bulk modulus,and volume thermal expansion coefficients of 15 kinds solids mentioned above were recalculated.All these work indicates that,the calculation of this paper on volume thermal expansion coefficients are good with experimental values,and for calculation of bulk modulus,the accuracy of our mehod is between the molecular dynamics simulations and the pseudopotential model in literature.