Fabrication of a surface-porous magnesium–aluminium alloy

•A surface porous Mg–Al alloy was fabricated successfully.•The Mg–Al eutectic alloy showed a selective corrosion character in HAc solution.•The porous formation mechanism was only governed by the α-Mg dissolution.•The finding is beneficial to the fabrication of the porous Mg-based alloys.

In this investigation, an acetic acid (HAc) aqueous solution was found to be an effective electrolyte for an Mg–Al eutectic alloy de-alloying treatment. The corrosion morphologies showed that the Mg–Al eutectic alloy had an obvious selective corrosion character in the HAc solution. The pore formation mechanism was only governed by the α-Mg dissolution. With prolonged corrosion time, the de-alloying rate was slowed down due to corrosive ion transfer becoming difficult at the corrosion interface.