Hemming for improvement of joint strength in aluminium alloy and carbon fibre-reinforced thermoplastic sheets

Abstract. To increase the joint strength in hemmed aluminium alloy and carbon fibre-reinforced thermoplastic (CFRTP) sheets, two kinds of hemming processes were proposed. In a hemming process, hemming was combined with protrusions with structures on the surface on the aluminium alloy sheet. The protrusions with structure were firmly joined to the surface on the sheet by laser cladding with fine ceramic powders, and then the heated and softened CFRTP sheet material was compressed and infiltrating into the protrusions in hot pressing. In the other hemming process, hemming was combined with the aluminium alloy sheet with drilled holes. The heated and softened CFRTP was flowed into the holes in hot pressing. Each hot press condition was investigated. And then, the strength in the pull-out direction and the strength in the peel direction were measured and compared. The joint strengths by the proposed two hemming processes were larger than that by hemming only.