The influence of {101¯2} twinning on the corrosion behavior of AZ31B magnesium alloy

This study investigates the effect of twinning on the corrosion behavior of AZ31B magnesium alloy using solid solution heat treatment (SHT) and laser shock peening (LSP) techniques. The corrosion characteristics are assessed by scanning electron microscopy (SEM), scanning Kelvin probe force microscopy (SKPFM), zero resistance ammeter (ZRA), scanning vibrating electrode technique (SVET), and electrochemical tests. Results indicate that the twinning region in AZ31B magnesium alloy, enriched with {101¯2} tensile twins induced by laser shock, demonstrates increased corrosion susceptibility. This region exhibits higher electrochemical activity and an accelerated corrosion rate compared to the matrix region. Micro-galvanic coupling between the twinned and matrix regions promotes faster dissolution of the alloy. Additionally, the corrosion product film on the surface is extensively cracked and propagates to the matrix corrosion surface, confirming that {101¯2} tensile twins provide inadequate protection against corrosion in AZ31B alloy. [Display omitted] •A micro-galvanic corrosion occurs between the twin and the matrix•T-2 samples rich in {101¯2} tension twins exhibit accelerated corrosion as an anode•The corrosion product film did not provide effective protection•The order of corrosion tendency is T-2 (0 h) > T-1 (0 h) > T-2 (24 h) > T-1 (24 h) Materials science; Materials chemistry