Laser Joining of Different Polymer-metal Configurations: Analysis of Mechanical Performance and Failure Mechanisms

Abstract

Direct thermal laser joining of plastic and metallic materials is nowadays arising as an alternative technology for the generation of hybrid joints. The focus of this study is on analyzing the mechanical behavior and failure mechanisms of three polymer-metal configurations: lap, T and Arcan joint configurations. The metal was locally structured by pulsed laser radiation producing micro-patterns to improve adhesion of the polymeric part. Two micro-patterns were considered: low and high distance between pattern centers. Secondly, the opposite side of the micro-structured metal was irradiated by a Continuous Wave (CW) fibre laser to achieve the mechanical interlock between the two materials.The mechanical performance of lap, T and Arcan joint configurations was assessed by tensile-shear, pull-out and Arcan tests respectively. A comprehensive inspection of the interface was carried out after the mechanical tests. The mechanical performance revealed a meaningful influence of the distance between patterns for the three joint configurations. Furthermore, the Arcan results evidenced a meaningful influence of the angle between the joining plane and the orientation of the applied load. The morphological features of the detached surfaces showed different failure modes depending on the join configuration.