Ni-15%Mo合金熔体热物理性质的Monte Carlo模拟

采用EAM势对6×6×6的Ni-15%Mo合金熔体进行Monte Carlo模拟，通过对不同温度下获得的NVT系统的平衡态统计分析得出Ni-15%Mo合金熔体在过冷态和过热态时的热物理性质.通过构造系统生成新表面，表面张力做功使系统能量发生改变，从而得到液态表面张力的模拟结果.Ni-15%Mo合金熔体的表面张力在1500—2000 K的温度范围内，随温度的变化规律为σ=1.918-1.130×10^-3（T-T_m） N/m 关键词： Monte Carlo模拟 表面张力 比热 Ni-15%Mo合金

Monte Carlo simulation of thermophysical properties of Ni-15%Mo alloy melt

The Monte Carlo method with EAM potential is used to simulate the liquid Ni-15%Mo binary alloy system, from which the thermophysical properties hardly measured by experimental measurement can be obtained. The simulated surface tension of liquid Ni-15%Mo alloy at the melting temperature is 1.918 N/m, and the simulated temperature coefficient of surface tension as a function of temperature is σ=1.918-1.130×10^-3（T-T_m） N/m. Based on the simulated surface tension, the variation of viscosity and solute diffusion coefficient within the range of from 1500 K to 2000 K can be deduced. The result of the viscosity is η=0.895exp（2.209×10⁴/RT） mPa·s, that is, the viscosity constant is 0.895 mPa·s, and the apparent activation energy is 2.209×10⁴ J/mol. The diffusion coefficient can then be obtained by the Stokes（Sutherland）-Einstein equation as D=9.803×10^-8exp（-3.643×10⁴/RT） m/s²， where the activation energy is 3.643×10⁴ J/mol. From the relationship between system energy and temperature, the specific heat of liquid Ni-15%Mo alloy at different temperatures can be determined to be C_p=37.313-1.425×10^-2（T-T_m） J·mol^-1·K^-1.