合金元素在Mo中的活度和溶解度

Activity and solubility of alloying elements in Mo

基于Miedema模型及其相关物性参数研究合金元素在Mo中的活度和溶解度,并将预测结果与第一性原理计算及其他经验方法的结果进行比较。结果表明:合金元素在Mo中的活度随着温度及合金元素浓度的增加而增大;在相同浓度条件下,主族元素Ge、Al和Si在Mo中的活度较小,过渡族元素Ti、Hf、Nb、Zr和Re等活度较大,后者往往成为钼基合金的主要合金化元素。溶解度研究表明,合金元素在Mo中的溶解度受到原子尺寸因素、电子密度因素和电负性因素的影响,而合金元素在Mo中的溶解热则是后两个因素的综合反映。以溶解热和原子尺寸参数为横纵坐标建立Miedema-Alonso图发现,其与Mo原子尺寸差异小于15%,且在Mo中溶解热在-20～20 kJ/mol之间的合金元素有望在Mo中获得较大的溶解度。

The activity and solubility of alloying elements in Mo were investigated by using Miedema’s model and its related physical parameters,and these results were compared with the results predicted by the first-principle calculations and other’s empirical approach.These results show that the activity of alloying elements in Mo increases with the increasing temperature and alloying concentration.Under the same concentrations,the activities of main group elements Ge,Al and Si in Mo are small,and the activities of transition elements Ti,Hf,Nb,Zr,and Re are relatively large,which the latter should be chosen as the main alloying elements of Mo-based alloys.The solubility results also point out that the solubility of alloying element in Mo is influenced by atomic size factor,electron density factor,and electronegativity factor.And the solution heat of alloying elements in Mo is a comprehensive reflection of the last two factors.Furthermore,Miedema-Alonso plot was established by using the solution heat of alloying elements in Mo and atomic size parameters as the horizontal and vertical coordinates,respectively.It is found that the alloying element,which its atomic difference from Mo is smaller than 15%and its solution heat in Mo lies in the rang from?20 to 20 kJ/mol always has large respectively solubility limit in Mo.