Zr含量对Al3(ZrxEr1-x)相价电子结构与合金性能的影响

Effects of Zr Content on Valence Electron Structure of Al3(ZrxEr1-x) Phase and Mechanical Properties of Alloys

摘要:

用固体与分子经验电子理论(EET)计算研究了微量元素Er，Zr添加到铝合金中产生的Al3Er和Al3(ZrxEr1-x)相的价电子结构，探讨了不同Zr含量对Al3(ZrxEr1-x)相各电子结构参数的影响。计算结果表明：随着Zr原子含量的增加，表征强度性能的最强键上的共价电子对数nα和相结构形成因子S会减小，这说明合金熔体凝固过程中Al3Er相优先析出，Al3(ZrxEr1-x)和Al3Zr相则在随后的热处理工艺过程中析出，而且Zr原子的添加对合金的强度影响不大；表征塑性性能的晶格电子密度参数ρ先增大后减小，说明Zr原子的加入对合金的塑性有明显的改善。

Abstract:

The valence electron structures of Al3Er and Al3(ZrxEr1-x) phases resulted from minor elements Er and Zr addition to Al alloys were calculated according to the empirical electron theory in solid and molecule (EET). Effects of Zr contents on the valence electron structure parameters of Al3(ZrxEr1-x) phases were discussed. The calculation results show that with the increase of Zr atom content, both the covalent electron pairs nα on the strongest bond for strength properties characterization and the phase structure forming factor S decrease, which indicates Al3Er phases firstly precipitate during the solidification process and Al3Zr and Al3(ZrxEr1-x) also precipitate during the subsequent heat treatment; whereas, Zr addition has few influence on the strength of the alloys. The density of crystal lattice electron ρ for plastic properties characterization increases first and then decreases, revealing that Zr addition can obviously improve the plastic properties of the alloys.