金属材料弹性常数与温度关系的分子动力学模拟

Molecular Simulation of the Relationship between Elastic Constants of Metals and Temperature

基于固体物理微观理论,导出了金属材料密度与温度之间的关系式,应用此关系式计算出的不同温度下材料密度与试验结果能较好吻合。在讨论了固体弹性常数与原子间相互作用势之间关系的基础上,给出了金属固体分子动力学模拟原子间相互作用势函数的选择原则;提出了基于变化调整晶体结构和密度来间接反映温度变化影响的弹性常数分子动力学模拟算法,并对计算过程进行了说明,为分析高温材料性能提供了一条新途径。基于所提算法,给出了常温和912℃下弹性模量和泊松比的计算实例,计算结果与试验结果吻合良好。

The relationship between the metal material density and temperature was deduced from thermal expansion analysis based on solid physics microscopic theory.The material densities at different temperatures calculated by applying the relationship agreed well with the experimental data.On the basis of the discussion about the relationship between the elastic constants and interatomic potentials of metals,some advices on energy potentials configuration choice were provided.A new approach of molecular dynamics simulation was developed to calculate the elastic constants of metals based on the influence of temperature change by adjusting crystal parameters including structure and density.The corresponding computation procedure is described and it can provide a new method to analyze the material properties at high temperatures.Examples of computing elastic modulus and poisson ratio at room-temperature and 912℃ were given by applying the proposed method.The results were in a good accord with known test data.