Experimental and numerical study on the new technology of combining 7075‐W Al alloy with carbon fiber reinforced plastic composites

Abstract A hybrid composite material was obtained by stacking carbon fiber reinforced plastic (CFRP) onto 7075‐W Al alloy sheet. Mechanical properties of the CFRP/Al hybrid composite material were measured by tensile and flexural tests. To investigate the flow of the epoxy, the thinning was measured using an optical microscope and the defects were observed by a scanning electron microscope. A finite element model was established to predict the thickness and the contact pressure distributions of the CFRP/Al hybrid composite material during the forming process. The results showed that the tensile strength (TS) of the CFRP/Al hybrid composite was increased by 10% and the fracture strain was increased by 24% compared with the single 7075 Al alloy. The flexural strength (FS) and the displacement of the loading nose were improved by 13% and 75%, respectively. According to the microstructure observation, large cracks in the epoxy could be found on the side wall of the U shape part. The results of numerical analysis indicated that the low contact pressure at side wall was the main reason for the decrease of the tensile and FS and the delamination between laminates.