This study reports on de-alloying corrosion in a heat-affected zone (HAZ) of marine propeller Mn-Al bronze. The HAZ consisted of alpha, beta* phases and a 2-5 mu m thick alpha/beta* interface layer. The beta* phase having high aluminium content was expected to corrode first, it found that the de-alloying initiated from the alpha/beta* interface layer. TEM diffraction patterns and images showed Cu3Mn2Al and orthorhombic L-J precipitates in Cu2MnAl matrix plus numerous dislocations and strain fields, which caused the layer to be corroded first. This study suggests that microstructure is a critical factor for corrosion more than the highly reactive aluminium content. (C) 2018 Elsevier B.V. All rights reserved.