Al-Cu-RE三元合金热力学性质的Miedema理论计算

发布时间：2018-05-06 23:22

本文选题：Al-Cu-RE + Miedema理论　；参考：《稀有金属材料与工程》2015年03期

【摘要】：合金形成焓是确定合金的稳定性及其非晶形成能力的重要因素。采用Miedema理论和几何外推模型相结合,预测了Al-Cu-RE(RE=La~Lu)体系液态合金整个成分范围的混合焓。计算结果表明:Al-Cu-RE三元体系的混合焓比Al-Cu二元合金的混合焓更负,稀土元素与Al、Cu之间的化学势差对混合焓的贡献起主要作用。当铝与稀土元素含量相同时,随着铜含量的减少,合金混合焓越来越负,从而表明在Al-Cu合金中加入稀土元素有利于Al-Cu-RE三元合金的形成。同时较负的混合焓是合金体系易于非晶化的重要条件之一,也说明Al-Cu-RE三元体系非晶形成能力较强。计算了Al8Cu4RE和Al Cu RE等三元化合物的形成焓,计算得到的Al Cu RE的形成焓比相应的Al8Cu4RE的形成焓要负,说明Al Cu RE更稳定;同时计算了金属间化合物Al(Cu1-xREx)3、Al(Cu1-xREx)、Al2(Cu1-xREx)的形成焓随稀土含量变化趋势。计算结果为Al-Cu-RE体系非晶形成的成分设计和相关性能研究提供了重要的热力学数据。
[Abstract]:The formation enthalpy of the alloy is an important factor to determine the stability of the alloy and its amorphous formation ability. Based on Miedema theory and geometric extrapolation model, the mixing enthalpy of the liquid alloy in the Al-Cu-RERE-RE-LA-LU) system has been predicted in the whole composition range. The results show that the mixing enthalpy of the 1: Al-Cu-RE ternary system is more negative than that of Al-Cu binary alloy. The chemical potential difference between rare earth elements and Alnion Cu plays a major role in the contribution of mixing enthalpy. When the contents of aluminum and rare earth elements are the same, with the decrease of copper content, the mixing enthalpy of the alloy becomes more and more negative, which indicates that the addition of rare earth elements to the Al-Cu alloy is beneficial to the formation of Al-Cu-RE ternary alloy. At the same time, the negative mixing enthalpy is one of the important conditions for the alloy system to be easy to be amorphous, which also indicates that the Al-Cu-RE ternary system has strong amorphous formation ability. The enthalpy of formation of ternary compounds such as Al8Cu4RE and Al-CuRE is calculated. The calculated enthalpy of formation of Al-CuRE is negative than that of corresponding Al8Cu4RE, which indicates that Al-CuRE is more stable. The formation enthalpy of the intermetallic compound AlnCu1-xREx3 (Cu1-xREx-Al2Cu1-xREx3) was calculated with the change of rare earth content. The calculated results provide important thermodynamic data for the composition design of amorphous formation of Al-Cu-RE system and the study of related properties.
【作者单位】：广西教育学院;广西大学;
【基金】：国家自然科学基金(51061004) 广西高校科学技术研究项目(2013YB377)
【分类号】：TG146.21

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