Experiments have shown that Si has an effect on the precipitation behavior of S nano-phases in Al-Cu-Mg alloy.However,the microstructure of the S(Al_(2)CuMg)/Al interface,especially when Si is segregated,remains uncle...Experiments have shown that Si has an effect on the precipitation behavior of S nano-phases in Al-Cu-Mg alloy.However,the microstructure of the S(Al_(2)CuMg)/Al interface,especially when Si is segregated,remains unclear.Herein,we performed first-principles calculations to address this issue theoretically.(i)The accurate values of surface energies for three low-index surfaces(001),(010),and(100)of the Al_(2)CuMg phase,including both non-stoichiometric and stoichiometric surfaces,were calculated using two different methods.(ii)The lowest energy structure of the Al_(2)CuMg(001)/Al(021)interface was obtained by comparing the energies and interface separation work of interface supercells containing different atoms.(iii)The segregation behavior of solutes Si and Sc at the Al_(2)CuMg(001)/Al(021)interface were explored at the atomic level.The results suggest that Sc tends to substitute Al atoms on the Al matrix side of the interface,while Si prefers to substitute Al atoms on the Al_(2)CuMg side.All Cu and Mg atoms at the interface are energetically forbidden from being substituted.展开更多
文摘Experiments have shown that Si has an effect on the precipitation behavior of S nano-phases in Al-Cu-Mg alloy.However,the microstructure of the S(Al_(2)CuMg)/Al interface,especially when Si is segregated,remains unclear.Herein,we performed first-principles calculations to address this issue theoretically.(i)The accurate values of surface energies for three low-index surfaces(001),(010),and(100)of the Al_(2)CuMg phase,including both non-stoichiometric and stoichiometric surfaces,were calculated using two different methods.(ii)The lowest energy structure of the Al_(2)CuMg(001)/Al(021)interface was obtained by comparing the energies and interface separation work of interface supercells containing different atoms.(iii)The segregation behavior of solutes Si and Sc at the Al_(2)CuMg(001)/Al(021)interface were explored at the atomic level.The results suggest that Sc tends to substitute Al atoms on the Al matrix side of the interface,while Si prefers to substitute Al atoms on the Al_(2)CuMg side.All Cu and Mg atoms at the interface are energetically forbidden from being substituted.
