高级检索

金属镥定向凝固过程中杂质分布的理论研究

Theoretical Study on Impurity Distribution during Directional Solidification of Lutetium

  • 摘要: 高纯镥作为稀土金属,有着重要研究价值。文章通过理论计算分析了真空电子束熔炼和定向凝固下镥锭中杂质Fe和Al的分布,研究了蒸发和分凝效应耦合作用下金属镥的提纯效果以及影响机制。结果表明,电子束定向凝固金属镥过程中,虽然杂质Al的饱和蒸气压大于Fe杂质的饱和蒸气压,但Fe杂质蒸发传质系数大于杂质Al。金属镥中杂质Fe和Al分布不仅受固液界面分凝的控制,还受气液界面蒸发的控制,金属镥锭高度60%以下区域的Fe含量由4.836×10−3降低到了6.2×10−5,Al含量由7.75×10−4降低到了3.3×10−8,有着较好的提纯效果。熔炼温度和凝固速率是影响电子束定向凝固镥金属过程中杂质分布的两个重要参数。一个纯度较高且分布均匀的镥金属锭可以通过合理控制熔体温度和凝固速率来获得。

     

    Abstract: High purity lutetium, as a rare earth metal, has important research value. In this study, the distribution of impurities Fe and Al in lutetium ingots under vacuum electron beam melting and directional solidification was analyzed through theoretical calculation. The purification effect and influencing mechanism of metal lutetium under the coupling effect of evaporation and segregation were studied. The results show that during the process of electron beam directional solidification of lutetium, although the saturated vapor pressure of impurity Al is greater than that of Fe impurity, the evaporation mass transfer coefficient of Fe is greater than that of Al. The distributions of impurity Fe and Al in metal lutetium are not only controlled by solid-liquid interface segregation, but also by gas-liquid interface evaporation. The Fe content in the area below 60% of the height of lutetium ingot decreased from 4.836×10−3 to 6.2×10−5, and the Al content decreased from 7.75×10−4 to 3.3×10−8, indicating a good purification effect. Temperature and solidification rate are two important parameters that affect the distribution of impurities in the process of electron beam directional solidification of lutetium. A lutetium metal ingot with high purity and uniform distribution can be obtained by reasonably adjusting the melt temperature and solidification rate.

     

/

返回文章
返回