Investigating the combined effects of wide stacking faults and grain size on the mechanical properties and corrosion resistance of high-purity Mg.

In this work, the wide stacking faults (SFs) were introduced into high-purity Mg through large plastic deformation or annealing at the same time as adjusting the grain size, and the combined effects of wide SFs and grain size on the mechanical properties and corrosion resistance of high-purity Mg were clarified. It is found that the symmetrical rotary swaging can significantly refine the Mg grain and eliminate the wide SFs produced during the warm extrusion process, while the annealing can introduce the wide SFs with much higher density into the coarsened grains again. The grain refinement derived from rotary swaging after warm extrusion results in increased mechanical strength and corrosion resistance. The high-density wide SFs formed during annealing can improve the strength of high-purity Mg to more than 210 MPa, which is comparable to that of some Mg alloy. Meanwhile, the substantial coarsened grain only leads to slightly lowered corrosion resistance because the high-density SFs can delay the corrosion process. These findings provide novel approaches for achieving the desired mechanical properties and corrosion resistance of high-purity Mg, which can catapult its application in specific areas forward. • The high-density wide SFs were introduced into high-purity Mg with a specific process. • The SFs help the achievement of high strength and good ductility for high-purity Mg. • Grain size is more decisive for corrosion resistance of high-purity Mg than SFs. [ABSTRACT FROM AUTHOR]