Interfacial structure and bonding mechanism of AZ31/carbon-fiber-reinforced plastic composites fabricated by thermal laser joining

Multi-material joining is attracting attention in automotive industry due to the potential for lighter weight vehicles, fuel savings, and reduced emissions. The aim of present work is to understand the bonding mechanisms between metal and plastic/composites joints and improve the multi-material joint strength. In this work, the effect of thermal oxidation of Mg alloy sheets on the strengths of Mg–CFRP (carbon-fiber-reinforced plastic) lap joints prepared using laser-assisted metal and plastic joining technique was investigated. Characterization techniques including scanning electron microscopy, transmission electron microscopy, micro-computed tomography, x-ray photoelectron spectroscopy (XPS), and atom probe tomography (APT) were used to study the underlying mechanisms of the effect of thermal oxidation. The formation of bubbles, mechanical interlocking and chemical reactions at the joint interface were the three key factors that influenced the strength of joints. Thermal oxidation increased joint strength significantly through suppression of bubble formation, CFRP decomposition and the setting up of mechanical interlocking effects at the joint interface. Moreover, MgCO3, MgO1+x, and Mg(OH)2 phases were detected by XPS analysis at the joints prepared with thermally oxidized Mg alloy sheets. The presence of the high O/Mg ratio phases was also confirmed by the APT analysis. The formation of these phases confirmed the chemical reactions between the MgO and CFRP matrix at the nanometer level and is considered to contribute to the increase of the joint strength.

» Author: Barton Mensah Arkhurst, Jae Bok Seol, Youn Seoung Lee, Mok-Young Lee, Jeoung Han Kim

» Reference: 10.1016/j.compositesb.2018.12.002

» Publication Date: 06/12/2018

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This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement Nº 768737


                   




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