The preparation and mechanical properties of nano-magnesium alloy bulks.

In this paper, nanocrystalline (nc) AZ91 magnesium alloy bulks, with average grain sizes of ∼15 nm, were processed via the combined processing of hydrogenation-disproportionation-desorption-recombination (HDDR), spark plasma sintering (SPS) and hot extrusion. The effects of different sintering temperatures and holding times on the sintering properties of magnesium alloy were analyzed and the optimum SPS sintering process parameters of nanocrystalline AZ91 powder were determined. The tensile strength of nc AZ91 magnesium alloy rods is up to 267 MPa at room temperature. Meanwhile, when the grain size is less than 20 nm the particular mechanical behavior of nc magnesium alloy emerged, which implies an inverse Hall-Petch relationship. • We produced the nc magnesium alloy bulks by the combination of HDDR, SPS and hot extrusion with average grain sizes ∼15 nm. • Grain sizes of nc AZ91 powders prepared by HDDR have little change after high temperature sintering and hot extrusion. • The tensile strength of nc AZ91 magnesium alloy rods is up to 267 MPa at room temperature. • The yield strength value of the nc A91 bulk prepared in this paper may be an inverse Hall-Petch relationship curve. [ABSTRACT FROM AUTHOR]