Abstract
High-energy ball milling was employed to synthesize Al-Zn-Mg-Cu alloy (7000 series) with high weight percentage of nickel from its elemental powders via mechanical alloying mechanisms. The mixed powders underwent 15 hrs of milling time, 380 rpm speed and 12:1 balls/powder weight ratio. The milled powder samples were cold compacted and sintered thereafter. The sintered compacts which were homogenized at 450°C for 1.5 h and aged at 124 °C for 24 hrs. The milled powders and heat-treated Al alloy products were characterized via scanning electron microscopy, and energy dispersive spectroscopy. The results revealed that optimum milling time of 15 hrs has led to the formation of solid solutions of Al-Zn-Mg-Cu with Ni. The mechanical alloying mechanism allows for the attainment of Al solid solutions with amount of nickel and dopants Zn, Mg, and Cu at a concentration that exceeds their equilibrium solubility compared with melting and crystallization in conventional processes. The outcomes showed that the hardness of the sintered Al-Zn-Mg-Cu-Ni alloys compacts was enhanced following the artificial aging treatment.