An engineering route to synthesize stable bulk nanocrystalline magnesium with an average grain size of 20 nm

A simple and effective route to preparing bulk nanocrystalline (NC) pure Mg with an average grain size of 20 nm is first proposed by hydrogenation-disproportionation-desorption-recombination (HDDR) followed by spark plasma sintering (SPS) and hot extrusion (HE) techniques. NC Mg is thermodynamically super-stable against annealing at 550 °C and straining under compression and tension. Moreover, the as-extruded NC Mg samples show high tensile yield stress (TYS) of 259 MPa and compressive yield strength (CYS) of 157 MPa, which are about 2 times and about 7–10 times higher than those of their coarse-grain counterparts and the as-cast samples, respectively.