Negatively correlated corrosion and stress corrosion cracking of Mg-Al-Mn-Ca based alloys

A negative correlation between corrosion and stress corrosion cracking (SCC) for Mg-Al-Mn-Ca-(Ce/Y) alloys is revealed. Specifically, high-level Al solute and trace Ce/Y alloying enhance the corrosion resistance via reducing Volta potential difference and forming dense corrosion product film. However, the compact film breaks severely during SCC, aggravating the initiation of cracks. Meanwhile, the numerous second phases facilitate H diffusion and adsorption, exacerbating the hydrogen enhanced decohesion in Ce/Y-containing alloy. The film rupture induced anodic dissolution and hydrogen enhanced decohesion dominate the SCC. This work shed light on fundamental understanding of the relationship between corrosion and SCC.