Effect of layer thickness on bonding strength of Al/epoxy resin joints via interpenetrating phase layer

摘要

Open porous Aluminum (Al) layer was fabricated on Al substrate, and epoxy resin (epoxy) was infiltrated into the layer and cured. Al and epoxy formed "interpenetrating phase layer (IPL)", and interlocked three-dimensionally each other. The volume fraction of epoxy in the IPL was fixed at 0.8, and the effect of the thickness of the IPL (t(IPL)) on the tensile strength (sigma(j)) was investigated. sigma(j) increased when tin was in the range of 0-2 mm, and decreased when t(IPL) was 5 mm and 10 mm. Based on observations of fractured surfaces, this decrease in cri was due to incomplete infiltration of epoxy. When t(IPL) was in the range of 0-2 mm, separation of Al and epoxy and rupture of epoxy occurred at the epoxy/IPL interface edge, which was the starting point for the fracture. For t(IPL) 0.5 mm, the area fraction of epoxy at the epoxy/IPL interface was lower than 0.8, resulting in significant stress concentration. tin needs to be higher than the pore diameter in the Al substrate. By controlling t(IPL), Al/IPL/epoxy joints were obtained with a tensile strength of 38.0 MPa.