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通过晶胞平移获得Al-Zn-Mg-Cu合金中α-Al,Al3Sc及η相原子集团模型,采用自编软件建立α-Al/液态Al界面、α-Al/Al3Sc界面原子团模型.用递归法计算合金中各组织的态密度、结合能、费米能级,合金元素Sc与空位相互作用能等电子参数.依据电子参数解释合金晶粒细化、腐蚀的物理本质.研究表明:Al3Sc从液态金属析出时释放的能量比α-Al从液态金属析出时所释放的能量少,可先于α-Al从液态金属中析出;且α-Al与Al3Sc的界面能远低于α-Al/液态Al的界面能,Al3Sc可为α-Al的形核生长提供条件,增加α-Al的形核率,细化晶粒.Sc吸引空位,降低空位及溶质原子的扩散能力,使晶界无沉淀带宽度变窄,进而减小晶界与晶内的电极电位差,提高合金的耐蚀性能.
The α-Al, Al3Sc and η phase atomic group models of Al-Zn-Mg-Cu alloy were obtained by unit cell translation, and the atomic cluster model of α-Al / Al interface and α-Al / Method to calculate the density of states, the binding energies, the Fermi level, the interaction energy between the alloying elements Sc and the vacancies, etc. The electronic properties of the alloys were also studied.The results showed that the Al3Sc transition from The energy released when the liquid metal is precipitated is less than the energy released when the α-Al is precipitated from the liquid metal and can be precipitated from the liquid metal prior to the α-Al; and the interface energy between the α-Al and the Al3Sc is much lower than that of the α-Al / Al3Sc can provide the conditions for the nucleation growth of α-Al, increase the nucleation rate of α-Al and refine the grains. Sc attracts vacancies and reduces the vacancy and the diffusion ability of solute atoms, Narrowing the width of the precipitation zone, thereby reducing the grain boundary and crystal electrode potential difference, improve the corrosion resistance of the alloy.