Bulk Mg–3Al–Zn alloy with ultrafine grain size produced by powder metallurgy

Ultrafine-grained Mg–3Al–Zn alloys with an average grain size of 180 nm have been made by powder metallurgy. First, the nanocrystalline powders with mean grain size of 45 nm were produced by ball milling under argon atmosphere, and then through vacuum hot pressing at 633 K for 40 min and warm extrusion at 373 K, bulk solid samples were compacted successfully from the mechanically milled powders, and the relative density of the samples was about 98.87% (1.8003 g/cm3). XRD, SEM and TEM analysis showed that the microstructure of the samples consists of homogeneous equiaxed grains and grain growth has taken place during the consolidation process.

Research highlights► The ultrafine grain Mg–3Al–Zn alloy with an average grain size of 180 nm can be produced by powder metallurgy. ► The nanocrystalline Mg–3Al–Zn powders with an average grain size of 45 nm were produced by ball milling. ► The consolidated samples had a final density of 1.8003 ± 0.006 g/cm3, which corresponds to 98.87 ± 0.3% of theoretical density.