Effects of surface treatments and bonding types on the interfacial behavior of fiber metal laminate based on magnesium alloy

Highlights: • Phosphating treatment can significantly improved the surface energy and wettability of magnesium alloy. • Phosphating treatment and high polymer adhesive film have observably improved the tensile strength and interfacial fracture toughness of fiber metal laminate based on magnesium alloy. • Rougher surface was more conducive to enhance the bonding strength of fiber metal laminate based on magnesium alloy. Fiber metal laminates based on magnesium alloys (MgFML) with different surface treatments and different bonding types were tested and analyzed. By using dynamic contact angle measurement and scanning electron microscopy (SEM), it was found that phosphating treatment can significantly improve the surface energy and wettability of magnesium alloy, and the surface energy of phosphated magnesium alloy was approximately 50% higher than that of abraded-only magnesium alloy. The single cantilever beam (SCB) test showed that the interfacial fracture energies of directly bonded MgFMLs based on abraded-only magnesium and abraded + phosphated magnesium were 650 J/m² and 1030 J/m², respectively, whereas the interfacial fracture energies of indirectly bonded MgFMLs were 1650 J/m² and 2260 J/m², respectively. Phosphating treatment and modified polypropylene interleaf were observed to improve the tensile strength and interfacial fracture toughness of MgFML. In addition, the rougher surface was more conducive to enhance the bonding strength and interfacial fracture toughness of MgFML.