Experimental investigation of the strength of polymer-steel direct adhesion (PSDA) joints with micro-structures ablated by laser

The key issue for polymer-steel direct-adhesion (PSDA) technology is to find an effective and efficient way to enhance the adhesion strength. A high-power precision laser processing method was utilized to form a periodic microstructure on the metal surface before PSDA joining. The corresponding theoretical model was proposed to optimize the processing parameters and establish the relationship between microstructures and adhesion fracture energy. Additionally, single-lap tensile shear tests of PSDA samples with various mircostructures were carried out. The experimental results show that the proposed method could increase the ultimate tensile load by nearly 1.5 times higher than the traditional chemical surface pretreatment. Due to the processing of periodic microstructure could be controlled accurately by machines, the dimensional precision was improved. The investigation also discovered that the packing arrangement of interfacial microstructures affects the adhesion strength and fracture energy, but independent of the roughness. The present method is demonstrated to be an effective, efficient, and economic interface treatment for polymer-steel hybrid structures.