Abstract: This study focuses on the stress corrosion behavior of the Mg-Zn-Zr alloy system in extruded condition (tubes). The binary alloys Mg-Zn and Mg-Zr are compared to the ternary alloy system regarding microstructure, hardness, bending strength and corrosion behavior. Cring tests in Ringer solution are used to evaluate the stress corrosion properties. POM polymer, being corrosion resistant and neutral to the Mg-corrosion, was chosen to build up the test set-up for the C-ring tests. Bending tests have been done to determine the elastic-plastic region of the samples – before starting the C-ring experiments. Twinning as a result of deformation increases the corrosion rate and is most prominent at the Mg-Zr alloy. Signs of pitting corrosion to different extents have been found in all alloys investigated. The Mg-Zn alloy corrodes the most within this alloy group. Plastic deformation is increasing the corrosion, however, signs of stress corrosion cracking could not be found.
Authors: Petra Maier, Nico Ostermeier, Jens Wicke, Sihang You, and Norbert Hort
Keywords: magnesium, Mg-Zn-Zr, C-ring test, stress corrosion, corrosion morphology