基于不同模型的硅铁熔体热力学性质计算

Calculation of thermodynamic properties of Fe-Si melt based on different models

采用熔体热力学模型计算熔体热力学性质是冶金物理化学研究的重要内容。基于Miedema模型和作用浓度模型对硅铁熔体混合焓和活度进行了计算,并与其他模型计算结果及实测数据进行了对比分析。计算结果表明,Miedema模型相对于作用浓度模型的混合焓计算结果与实测值差距较小。采用作用浓度模型计算硅铁活度时,需要依据已有的活度数据拟合得到硅铁金属间化合物的生成吉布斯自由能,且采用活度拟合得到的硅铁金属间化合物生成自由能与试验值差距较大。对已有热力学模型的结果对比分析表明,对熔体微观结构的准确定量描述是建立物理意义清晰且能准确预报熔体性质的热力学计算模型的关键。

It is an important content of the research on physical chemistry of metallurgy to calculate thermodynamic properties of melts by melt thermodynamic models.The Miedema model and the computational model of action con-centration were used to calculate the mixing enthalpy and activity of Fe-Si melt and these results were compared with other calculated results and experimental data.Results showed that compared with the calculated results of the com-putational model of action concentration,the difference between the results of the Miedema model and the experi-mental data was relatively smaller.The existing data of activity was needed to fit the Gibbs free energy of Fe-Si compounds before the computational model of action concentration was used to calculated the activity of silicon and i-ron,and the calculated results were greatly different from the experimental values.The comparison of calculated re-sults of existing thermodynamic models showed that the accurate quantitative description of the microstructure of melts was the key to establish a thermodynamic calculation with clear physical meanings and the accurate function to predict properties of melts.