Strong metal/non-polar plastic dissimilar joints are highly demanded for the lightweight design in many fields, which, however, are rather challenging to achieve directly via welding. In this study, we designed a laser processing pretreatment on the Al alloy to create a deep porous Al surface structure, which was successfully joined to the polypropylene (PP) via friction spot welding. A maximum joint strength of 29 MPa was achieved, the same as that of the base PP (i.e. the joint efficiency reached 100%), much larger than ever reported. The joining mechanism of the Al alloy and the PP was mainly attributed to the large mechanical interlocking effect between the laser processed Al porous structure and the re-solidified PP and the formation of chemical bond at the interface. The deep porous Al surface structure modified by laser processing largely changed the Al‒PP reaction feature. The evidence of the COAl chemical bond was first time found at the non-polar plastic/Al joint interface, which was the reaction result between the oxide on the Al alloy surface and thermal oxidization products of the PP during welding. This study provides a new way for enhancing metal-plastic joints via surface laser treatment techniques.

在许多领域中，轻型设计对坚固的金属/非极性塑料异种接头提出了很高的要求，但是，要通过焊接直接实现这种挑战非常困难。在这项研究中，我们对铝合金进行了激光加工预处理，以创建深孔的铝表面结构，该结构通过摩擦点焊成功地与聚丙烯（PP）结合在一起。达到的最大接缝强度为29 MPa，与基础PP相同（即接缝效率达到100％），比以前报道的要大得多。铝合金与PP的结合机理主要归因于激光加工的Al多孔结构与再凝固的PP之间较大的机械互锁作用以及在界面处形成化学键。通过激光加工改性的深孔Al表面结构大大改变了Al‒PP反应特征。C的证据首次在非极性塑料/ Al接头界面发现O Al化学键，这是铝合金表面的氧化物与PP在焊接过程中的热氧化产物之间的反应结果。这项研究提供了一种通过表面激光处理技术增强金属-塑料接头的新方法。