基于第一性原理的5083铝合金第二相理化性质研究
Study on the Physical and Chemical Properties of the Second Phase of 5083 Aluminum Alloy Based on the First Principles Calculation

为揭示5083合金第二相对合金性能影响机理，本文采用相图计算的方式，研究了5083合金中潜在的第二相种类及数量，并在此基础上，通过量子力学计算的方法，系统探究了合金中潜在各相的弹性常数以及与α-Al基体间费米能差值等理化性质。研究结果表明合金中潜在第二相主要有β-Al₃Mg₂、Al₆Mn、T-AlCuMgZn、E-AlCrMgMn、Mg₂Si、Al₃M_Do₂₂及Al₃Fe，其体模量从大到小排布顺序为Al₃Ti、Al₆Mn、Al₃Fe、E-AlCrMgMn、T-AlCuMgZn、Mg₂Si及β-Al₃Mg₂，剪切模量亦类同，除Mg₂Si与β-Al₃Mg₂互换位置。合金中与α-Al基体腐蚀电位差异大小排布顺序为Mg₂Si、Al₃Fe、Al₆Mn、T-AlCuMgZn、E-AlCrMgMn、β-Al₃Mg₂以及Al₃Ti，各相与α-Al基体间形成微腐蚀电池能力依次减弱。
This study investigates the impact of the second phase on the properties of 5083 alloy by employing phase diagram calculations to analyze the types and quantities of the second phase present. Utilizing quantum mechanics calculations, the elastic constants of potential phases in the alloy and the Fermi energy difference between the alloy and the α-Al matrix were examined. The findings reveal that the predominant second phases in the alloy consist of β-Al₃Mg₂, Al₆Mn, T-AlCuMgZn, E-AlCrMgMn, Mg₂Si, Al₃M_Do₂₂, and Al₃Fe. The bulk modulus ranking from highest to lowest are Al₃Ti, Al₆Mn, Al₃Fe, E-AlCrMgMn, T-AlCuMgZn, Mg₂Si, and β-Al₃Mg₂, with a similar trend observed for the shear modulus, except for Mg₂Si and β-Al₃Mg₂ switching positions. The difference in corrosion potential between the phases and the α-Al matrix follows the order of Mg₂Si, Al₃Fe, Al₆Mn, T-AlCuMgZn, E-AlCrMgMn, β-Al₃Mg₂, and Al₃Ti. The ability to form micro-corrosion cells between each phase and the α-Al matrix gradually diminishes.