Influence of dry-film lubricants on bond strength and corrosion behaviour of 6xxx aluminium alloy adhesive joints for automotive industry
Sprache des Vortragstitels:
Englisch
Original Tagungtitel:
Forum Aluminium
Sprache des Tagungstitel:
Englisch
Original Kurzfassung:
The application of dry lubricant on aluminium for automotive industry is indispensable for a high-quality forming behaviour. To provide a short production time those forming aids will not be removed during the joining step. The aim of this study was the characterization of the influence of dry lubricants on the bond strength and the corrosion resistance of an 6xxx aluminium alloy for automotive applications. For this purpose, samples with a well-defined surface were lubricated with 1 g/m² dry lubricant and joined with a commercial thermosetting 1K-epoxy structural adhesive. The bond strength was characterized by means of lap shear test. To evaluate the corrosion resistance of the adhered aluminium samples an immersion test in 5 w% NaCl-solution was used. Based on fracture pattern and Scanning electron microscopy with Energy dispersive X-ray spectroscopy (SEM/EDX) analysis, the corrosion behaviour could be described and possible corrosion mechanisms were evolved. The influence of dry lubricants load quantity was observed microscopically and mechanically. The environmentally induced degradation process of the adhesive was examined by the investigation of the volumetric change during testing and SEM analysis. Simulation of changes in the adhesive polymer matrix at the metal-adhesive-interface caused by dry lubricants were examined using polymer test procedures like Dynamic mechanical analysis (DMA), Differential scanning calorimetry (DSC) and Tensile tests. The results showed a significant effect of the forming aid on the corrosion resistance of adhered aluminium samples against corrosive infiltration of the metal-adhesive-interface.