Cu-Ni-Sn系合金调幅分解的第一性原理计算

Spinodal Decomposition of Cu-Ni-Sn Alloy by First Principle

通过第一性原理计算了不同成分的Cu-Ni-Sn固溶体的晶格常数、形成能与分解能。结果表明,Ni含量对Sn的调幅分解影响较大,Ni含量低于20%时,Sn的调幅分离能随着Ni含量的增加而升高,Ni含量为20%的Cu-Ni-Sn固溶体具有最强的分解趋势。当Ni含量高于20%,Sn的调幅分离能急剧降低,固溶体能稳定形成,不发生调幅分解。Ni的调幅分解趋势比Sn的调幅分解趋势强很多,且受Sn含量的影响很小。Sn的调幅分解过程中固溶体的体积应变小,而Ni在调幅过程中,固溶体体积增大。

Based first principle,the lattice constants,formation energy and demixing energy of Cu-Ni-Sn solid solution with different components were calculated.The results reveal that the Ni content has a great influence on the spinodal decomposition of Sn.When the Ni content is less than 20%,the demixing energy of Sn is increased with the increase of Ni content,and Cu-Ni-Sn solid solution with 20%Ni presents the strongest trend of spinodal decomposition.When the Ni content is more than 20%,the demixing energy of Sn is reduced sharply,and the solid solution with different Sn content can be formed stably and absence of spinodal decomposition occurrs.The spinodal decomposition trend of Ni is much stronger than that of Sn and little influenced by Sn content.The volume strain of the solid solution is decreased during the spinodal decomposition of Sn,while the volume of solid solution is increased during the spinodal decomposition of Ni.