基于等温状态方程数据计算不同温度的固体热膨胀系数

摘要

假设热膨胀对固体体积弹性模量B的影响与加压过程对体弹性模量的影响相似,即B仅为体积V的函数.利用等温状态方程实测数据获得体弹性模量对体积的变化规律B(V).基于B(V)和Grüneisen定律、Debye模型,并以室温(300 K)物性参数为初值逐次推算,获得Ag,Al,Au等15种材料在0～1 000 K(部分金属到2 000 K以上)的范围内各温度点的体积热膨胀系数值.数据对比显示计算值与实测值符合度高,这也表明了所提假设和方法的有效性.%The assumption proposed in this paper is that:for solids,the effect on bulk modulus B of thermal expansion is similar to it of pressing process,that is to say,B is merely the function of the volume V.The change rule B(V) of bulk modulus versus volume is obtained by data-fitting based on measured data of the isothermal EOS.Based on B (V) and Grüneisen law and Debye model,and taking physical parameters at room temperature (300 K) as initial values,after the step by step calculating,volume thermal expansion coefficients of 15 kinds solids such as Ag,Al,Au etc.are obtained,at each temperature within the temperature range from 0 K to about 1000 K (for several metals,the temperature range exceeding 2 000 K).The comparison of calculations and experiment data indicates the two are well agreed,and therefore demonstrates the effectiveness of the proposed analysis method and assumption of this paper.