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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—2000K的温度范围内,随温度的变化规律为σ=1.918-1.130×10-3(T-Tm)N/m.根据表面张力模拟结果,进一步推导出黏度在1500—2000K温度范围内的变化规律为η=0.895exp(2.209×104/RT)mPa.s,即Ni-15%Mo合金熔体的黏度常数为0.895mPa.s,表观活化能为2.209×104J/mol.将黏度的值代入Stokes-Einstein公式,从而得出溶质Mo在Ni-15%Mo合金熔体中的扩散系数随温度的变化关系为D=9.803×10-8exp(-3.643×104/RT)m/s2,即Mo在Ni-15%Mo合金熔体中的扩散激活能为3.643×104J/mol.对不同温度下Monte Carlo模拟获得的系统能量进行二次函数拟合,通过拟合函数得到的比热模拟结果表明,Ni-15%Mo合金熔体的比热对温度的依赖关系为Cp=37.313-1.425×10-2(T-Tm)J.mol-1.K-1.
The Monte Carlo simulation of 6 × 6 × 6 Ni-15% Mo alloy melt by EAM potential is carried out. By statistical analysis of the equilibrium state of the NVT system obtained at different temperatures, it can be concluded that the Ni-15% Mo alloy melt is undercooling State and superheat state thermophysical properties of the system by generating a new surface, the surface tension of the work done so that the system energy changes, resulting in liquid surface tension simulation results.Ni-15% Mo alloy melt surface tension 1500-2000K , The variation with temperature is σ = 1.918-1.130 × 10-3 (T-Tm) N / m. According to the simulation results of surface tension, the variation law of viscosity in the temperature range of 1500-2000K is deduced as η = 0.895exp (2.209 × 104 / RT) mPa.s, that is, the viscosity constant of Ni-15% Mo alloy melt is 0.895mPa.s and the apparent activation energy is 2.209 × 104J / mol.The values of viscosity are substituted into Stokes -Einstein equation. The results show that the diffusion coefficient of solute Mo in the melt of Ni-15% Mo alloy changes with the temperature as D = 9.803 × 10-8exp (-3.643 × 104 / RT) m / s2, The diffusion activation energy of Ni-15% Mo alloy melt is 3.643 × 104J / mol. The energy of system obtained by Monte Carlo simulation under different temperatures is quadratic function fitted The specific heat simulation results obtained from the over-fitting function show that the specific heat of the Ni-15% Mo alloy melt has a temperature dependence of Cp = 37.313-1.425 × 10-2 (T-Tm) J.mol-1.K -1.