Effect of electrolyte composition ratio of micro-arc oxidation on interlaminar strength of CFRP/Mg laminates

In this study, the micro-arc oxidation (MAO) processes in different electrolyte composition ratio were carried out on magnesium alloy sheets and then the carbon fiber reinforced polymer (CFRP)/magnesium alloys laminates were manufactured by using a cure process. The Mode I (peel) interlaminar strength was measured to systematically investigate the effects of the electrolyte concentration on interfacial bonding strength and failure mode of CFRP/Mg laminates in consideration of surface microstructures and roughness. The results show that with the increase of KOH in electrolytes solutions, the Mode I (peel) strength of FMLs performs sharply decreasing due to the decrease of roughness in local regions and the emergence of interspace between magnesium and epoxy. In addition, with the rise of KF in electrolytes solutions, the Mode I (peel) strength of FMLs declines rapidly on account of the sharply weakening of electro-chemical reactions, which causes the decrease of surface roughness. The specimen exhibits the optimal Mode I interlaminar strength of 2.04 N/mm when the KOH and KF concentration is 7.28 g/L and 2.9 g/L, respectively.