Enhanced corrosion resistance of high strength Mg–3Al–1Zn alloy sheets with ultrafine grains in a phosphate-buffered saline solution

•High-ratio differential speed rolling was used for grain refinement in AZ31.•Corrosion resistance was tested in a phosphate-buffered saline solution.•Corrosion resistance was greatly improved after HRDSR.•Fine grain size and strong basal texture improved the corrosion resistance.

The corrosion behaviour of ultrafine grained AZ31Mg alloy sheets with very high strength, which were prepared by high-ratio differential speed rolling (HRDSR) technique, was studied in a phosphate-buffered saline solution. The corrosion resistance was greatly improved after HRDSR. This result was attributed to the enhanced stability of the Mg(OH)2 layer due to the grain refinement and precipitation of various types of P-containing compounds on the stabilised Mg(OH)2 layer. The HRDSR technique has a good potential to be used for the development of magnesium sheets with good combination of mechanical and biocorrosion properties.