Study on oscillating laser welding of plastic and metal dissimilar materials

Plastics and metals are highly complementary in terms of strength and density, leading to a growing demand for plastic-metal dissimilar joining, particularly in electronics, rail transportation, and aerospace. For this reason, in this study, dissimilar welding of PA66/304 stainless steel and PET/304 stainless steel was realized by introducing an oscillating laser into conventional laser welding, respectively. The results show that the oscillating laser can improve the interfacial temperature uniformity through customized energy distribution, thus achieving high quality joining of different plastic species with metals. In addition to this, different plastic-to-metal joints were explored in detail in terms of tensile fracture failure forms. The sensitivity of the PA66 base material to heat input resulted in poor fracture molding of the joints. In contrast, the PET and 304 stainless steel joints showed excellent mechanical properties comparable to those of the base material. Through the research of the morphology of different regions of the fracture surface, it was found that the mechanical properties of the joints varied greatly in different weld positions, which was specifically manifested in the gradual enhancement of the joint toughness from the center of the weld to the two sides. Further analysis and testing of the fracture interface composition revealed the interfacial enhancement mechanism in the oscillating laser-induced heterogeneous joints.