Effect of processing history on corrosion behaviours of high purity Mg

Abstract

In this study, the effects of processing history on corrosion behaviours of pure Mg with controlled impurity content, were analysed systematically. Results revealed that impurity Fe and Si were precipitated into the Fe-Si phase by heat treatment prior to extrusion, leading to severe micro-galvanic corrosion of as-extruded pure Mg despite the same impurity contents with as-cast pure Mg. This result suggests that control of the actual tolerance limit, considering not only the impurity content but also the processing history, is required in designing alloys.