Effects of Deformation Texture and Twins on the Corrosion Resistance of Rolled AZ31 Mg Alloy Under 5% Uniaxial Compression

The deformation texture and twin effect of rolled AZ31 Mg alloy on the corrosion resistance in simulated body fluid (SBF) at room temperature were examined by potentiodynamic polarization and electrochemical impedance spectra. The corrosion morphology evolution after being immersed in SBF for 24 h has been analyzed by scanning electron microscope. The results show that the inhomogeneous deformation leaded to the obvious differences in the microstructure. The corrosion rate of rolled AZ31 Mg alloy decreased dramatically in the transverse direction (TD) plane, which mainly consisted of {0001} deformation texture, making TD plane be a lower surface energy, and thus a higher corrosion resistance, while the corrosion resistance of the plane with 45 degrees to TD direction (45TD plane) containing enormous {10-12} tension twins decreased after 5% uniaxial compression. The {10-12} tension twins accelerate the rate of corrosion procedure and pitting corrosion. Moreover, it is suggested that the deformation texture affects the corrosion behavior more than the twins do. This study indicates that the corrosion rate of AZ31 Mg alloy in SBF can be modified by the small uniaxial compression.