Zn-based alloys are widely used mainly as a protective coating in corrosive environments. Therefore, their research is mainly focused on their corrosion resistance properties and less effort is devoted to the study of mechanical properties, particularly to potential defects under mechanical load in certain applications.The aim of this paper is to characterize the cracking behaviour of three coatings: Zn, Zn5Al and Zn5Al0.5Mg on a steel substrate before and after plastic deformation. This behaviour has been studied by observation of cracks occurred on the surface and on the longitudinal section after bending in various angles (0°, 5°, 10°, 15°, 30°, 60°, 90° and 180°). Metallographic sections were prepared by conventional metallographic procedures and cracks were observed by laser scanning confocal microscopy (LSCM).Higher bending angles and more complex chemical composition led to formation of higher number and density of cracks, especially in case of alloy system containing Mg. With higher bending angles cracks transformed from interface, confined and surface cracks to through cracks. However, this type of crack exposes the substrate to the environment. Coatings after plastic deformation showed significantly improved cracking behaviour.Keywords: Zn-based alloys, crack, plastic deformation
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