Al-Mg-Sc合金中热力学平衡相的计算

Equilibrium phases and phase transformation of Al-Mg-Sc alloy through thermodynamic calculation

综合利用Miedema模型计算和MTDATA热力学计算软件与相应的Al基合金数据库,计算出含微量稀土元素Sc的Al-Mg合金可能析出的热力学平衡相,讨论组成对热力学平衡相的影响,分析各相的析出规律,重点分析Al3Sc相作为平衡相的变化规律。结果表明:微量稀土元素Sc在Al-Mg合金中仅以Al3Sc相的形式存在,采用Miedema模型计算出的Al3Sc的生成热为-35.11 kJ/mol,MTDATA分析证明Al3Sc相具有很好的热力学稳定性,理论上在温度高达900 K左右时才开始出现熔化且非常缓慢,可通过调节加入的稀土Sc的含量来控制主要强化相Al3Sc在铝镁合金中的含量。

Thermodynamic equilibrium phases of Al-Mg alloy with minor Sc contents and effects of chemical compositions on the equilibrium phases were researched by means of Miedema model and MTDATA software as well as the related databases of the general Al alloy. The possible thermodynamic equilibrium phases were analyzed through the MTDATA and compared with the results of the calculation through the Miedema model. The related phase transformation was discussed, the formation enthalpy （-35. 11 kJ/mol） of Al3Sc phase was calculated and the Al3 Sc phase＇s precipitation and stability until 900 K was studied and verified, which can be used to explain experiments phenomena of relevant alloys and is beneficial to the real Al-Mg alloy series strengthened and application.