Effects of the Surface Microstructure on the Joint Mechanical Properties of PA6/Aluminum Alloy Pressing Molded Specimen

Micro-nano structures on aluminum alloys surface were pretreated through polishing, and/or chemical etching. The PA6/ aluminum alloy specimens were fabricated by hot pressing in the self-made mold. The surface morphologies of the samples were examined by the field emission scanning electron microscopy and the laser scanning confocal microscope. Results show that the micro-nano sized rougher surface of alloy after sulphuric acid corrosion leads to a stronger mechanical interlock structure between aluminum alloy and PA6, resulting in highly improved joint strength. The mechanical properties show that the tensile shear strength of sample after sulphuric acid etching reaches 19.1 MPa, and the maximum interfacial joint strength of the studied sample is obtained. Compared with sample without chemical etching, the shear strength of the etched sample increases about 870%. At the same time, the failure mode is changed from adhesive type to cohesive type.