铝-稀土金属间化合物形成焓的计算

Calculations of Formation Enthalpies of Al-RE Intermetallics

详细分析了二元铝-稀土金属间化合物的形成焓的Miedema计算值和文献报道数据的误差分布。结果表明,计算值相比于文献中实验数据普遍呈现负偏差。为此,计算研究中需要针对铝-稀土元素重要的影响因子——稀土原子与铝原子的半径比来修正热力学计算模型。对铝-稀土金属间化合物的系列计算结果及其误差分析说明,修正的Miedema模型计算值更加接近实验值,误差由原来的36%缩小到目前的5%。并利用MTDATA热力学计算软件部分验算计算结果,证明依据新模型的热力学计算预测更加准确可靠。用新模型计算了常见的铝-稀土金属间化合物的形成焓,同时也计算了Al-Er,Al-Tb,Al-Gd等研究数据缺乏的铝-稀土金属间化合物的形成焓。

The error distribution between Miedema-calculated values and reference-reported values for formation enthalpies of binary Al-RE intermetallics was analyzed and it is known that the calculated results are commonly negative compared with those in references Therefore, an important influencing factor, radius ratio of RE atom to aluminum atom should be considered to modify the thermodynamic calculation model in the study. The calculation results of the modified model are more closed to the reported experiment results and the error was found to be reduced from 33.6% to 5%. The enthalpies of some common intermetallics of aluminum and rare earth were also checked by MTDATA for comparison. All that proved the modified calculating model are much more accurate and reliable. The common formation enthalpies of intermetallics of aluminum and rare earth as well as Al-Er, Al-Tb, Al-Gd, which are studied less, are calculated by the modified Miedema model.