Effect of Tensile Deformation Temperature on the Microstructure and Electrochemical Response of ZE10A Magnesium Sheet

The effect of tensile deformation temperature on the microstructure and electrochemical response of ZE10A magnesium alloy sheet was investigated. Tensile tests were carried out from nominal room temperature (25 °C) to 300 °C to impose different pre-deformation histories. Microstructural changes were evaluated by optical microscopy and grain size analysis, while the electrochemical response was assessed by open circuit potential (OCP), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution. The mechanical response showed a strong temperature dependence, with marked reductions in both yield strength and ultimate tensile strength as the deformation temperature increased. In contrast, the microstructural changes detected by optical microscopy were limited, with only a moderate increase in average grain size and no evidence of extensive grain growth. The stabilized OCP values and polarization responses remained comparatively similar among the investigated conditions, whereas EIS revealed an approximately 2.2-fold increase in the fitted effective interfacial resistance from 25 to 300 °C. Despite this clear relative change, the absolute resistance values remained characteristic of actively corroding magnesium. Overall, the results indicate that tensile deformation temperature strongly affects the mechanical response of ZE10A sheet, whereas the different electrochemical techniques show unequal sensitivity to the prior deformation condition. These findings contribute to the assessment of ZE10A for lightweight sheet applications involving cold and warm forming followed by exposure to chloride-containing environments.