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应用周国治提出的新溶液模型计算所得的Fe Mn Si中γ和ε相的Gibbs自由能 ,并考虑了Si的影响 ,重新导出了γ和ε相随温度变化的热力学参量 .用最小均方根方法将实验值拟合得到合金γ相的Neel温度与组分浓度 (摩尔分数 )的关系式 :TγN=6 7xFe+ 5 40xMn+xFexMn[76 1 + 6 89(xFe-xMn) ]- 85 0xSi.计算得到不同组分Fe Mn Si合金马氏体相变的临界驱动力ΔGγ→εc ,即合金在Ms 温度γ和ε相的自由能差 ,例如 ,Fe 2 7.0Mn 6 .0Si合金的ΔGγ→εc =- 1 0 0 .99J/mol,Fe 2 6 .9Mn 3.37Si的ΔGγ→εc =- 1 2 2 .1 1J/mol.ΔGγ→εc 与组分的依赖关系符合低层错能合金中fcc(γ)→hcp(ε)马氏体相变的临界驱动力表达式 ,即ΔGγ→εC =A·γ +B ,其中γ是层错能 (SFE) ,A和B为与材料相关的常数 .
The Gibbs free energy of the γ and ε phase in Fe Mn Si was calculated by the new solution model proposed by Zhou Guzhi. The thermodynamic parameters of γ and ε phase with temperature were re-derived considering the influence of Si. Method The experimental values were fitted to obtain the relationship between the Neel temperature and the component concentration (molar fraction) of the γ phase of the alloy: TγN = 6 7xFe + 5 40xMn + xFexMn [76 1 + 6 89 (xFe-xMn) The critical driving force ΔGγ → εc of the martensitic transformations of Fe Mn Si alloys with different compositions was obtained, that is, the free energy difference between the γ and ε phases of the alloy at Ms temperature, for example, ΔGγ → εc of Fe 2 7.0Mn 6 .0Si alloy, - 1 0 0 .99 J / mol, Fe 2 6 .9 Mn 3.37 Si ΔGγ → εc = - 1 2 2 .1 1J / mol.ΔGγ → εc The dependence of the composition on fcc (γ) → hcp (ε) martensite transformation critical driving force expression, that is ΔGγ → εC = A · γ + B, where γ is the fault energy (SFE), A and B are material-dependent constants.