Dynamic consolidation of nanostructured Al–7.5%Mg alloy powders

Dynamic consolidation was used to fabricate nearly fully dense nanostructured Al-7.5%Mg alloy samples. The nanostructured powders were produced by cryomilling and possessed a grain size of 22 nm. The consolidated samples had a final density of 2.567 g/cm^3, which corresponded to 98% of theoretical density. Peak broadening analyses have shown no significant increase in grain size or lattice strain during the consolidation process, as compared to the starting microstructure of the powders. The composite microstructure developed during the process is composed of nano-grains (<100 nm) surrounded by rims of ultrafine grains (300-500 nm). A microhardness value of 196 ± 8 HV0.3 was measured and the measurements are constant throughout the cross section; this was consistent with the nanoscale of the microstructure. Shear punch test was used to provide insight into the mechanical behavior of the samples and strength values of 446 ± 16 MPa were obtained. In all cases, the samples exhibited brittle behavior.