Crack behaviour in zinc coating and at the interface zinc-hot galvanised TRIP steel 800

•The behaviour of the crack at the interface of a bimaterial structure of zinc-TRIP steel 800 was studied.•It was found that the energy release rate decreases as soon as the crack approaches the interface and increases when crossing it.•The FE elastic modelling gave the following results: the probability for a crack to deflect was very high.•The same behaviour was supported by the volumetric approach results.•Finally, analytical and numerical findings were in a good agreement with microscopic examination obtained from SEM observations. In the present work, two paths of crack propagation in the bimaterial structure of zinc-TRIP steel 800 were investigated. Abaqus numerical simulation and singular integral equation method were used for the estimation of the crack behaviour at the interface. It was found that the energy release rate decreases as soon as the crack approaches the interface and increases when crossing it. The computation of the strain energies of deflection and penetration obtained from elastic modelling showed that the crack is more prone to deflect into the interface rather than to penetrate it. The same behaviour was supported by the volumetric approach results. Finally, analytical and numerical findings were in a good agreement with microscopic examination obtained from SEM observations.