Nanocrystallized Al-10.0%Zn-3.0%Mg-1.8%Cu(mass fraction)alloy powder was prepared by cryomilling,and then the nanostructured powder was consolidated into bulk material by spark plasma sintering(SPS).The microstructural evolution and phase transformation were studied.A supersaturated face-centered cubic solid solution is formed after cryomilling for 10 h,and the average grain size is 28 nm.Two typical nanostructures of the bulk nanostructured alloy are observed:primarily equiaxed grains with size of 150 nm,and occasionally occurring sub-micron grains up to 500 nm.Two types of MgZn2 particles precipitate during consolidation. One is the sub-micron particles distributed along the boundaries of the powders,and the other is fine particles with size of several nanometers in the matrix,especially at the boundaries of sub-micron grains.These second phase particles can be completely dissolved into matrix by proper solid solution treatment.
