Corrosion behaviour of ultrafine grained pure magnesium and ZK60 prepared by equal channel angular pressing in simulated body fluid and DMEM solution

Abstract

Corrosion behavior of pure magnesium and ZK60 subjected to equal channel angular pressing (ECAP) in simulated body fluid (SBF) and Dulbecco's Modified Eagle Medium (DMEM) solution has been investigated in the term deformation process. Pure magnesium and ZK60 were treated by the ECAP process up to two passes at 473 K. Then, the structure was observed by a digital optical microscope. The corrosion rate was measured by immersion testing in SBF and DMEM solution up to 24 hours, and the corroded surface was observed by a digital optical microscope. The microstructure of the material showed deformed and bimodal structure due to an intermediate level of deformation (equivalent strain=2). It was found that the structure influenced corrosion behavior. The ECAP process significantly improved the corrosion resistance of pure magnesium in SBF and DMEM. On the other hand, the corrosion resistance of ZK60 was reduced by the increase of ECAP passes due to precipitation in the material surface.