Effects of surface pre-treatments on Mode I and Mode II interlaminar strength of CFRP/Mg laminates

In this work, three different surface modification techniques, including grit blasting, micro-arc oxidation (MAO) and laser ablation, were respectively carried out on magnesium alloy sheets, and then the treated surfaces were evaluated for surface topography and surface roughness characteristics. Besides, the interlaminar strength and the interface failure characteristics of the CFRP/Mg laminates were examined, in order to comprehensively analyze the effects of the various pre-treatment techniques on interlaminar strength and fracture mechanisms of the CFRP/Mg laminates under Mode I (peel) and Mode II (shear) loading. The results show that the MAO treatment resulted in a slight increase of shear strength when compared with grit blasted surfaces, yet it yields worse peel strength outcome due to the weak MAO coating/Mg substrate interface. The laser ablation effectively enhances the overall interlaminar strength of the CFRP/Mg laminates under peel and shear loading. •The pores generated by laser ablation are local interconnected.•The micro-arc oxidation treated specimen shows low peel strength.•The failure occurred at MAO coating/Mg substrate interface under peel loading.•The laser treated specimen displays a good overall interlaminar strength.