Evaluation of grit-blasting as a pre-treatment for carbon-fibre thermoplastic composite to aluminium bonded joints tested at static and dynamic loading rates

• Published in: Composites. Part B, Engineering Vol. 185; p. 107765
• Main Authors: Ramaswamy, Karthik, O'Higgins, Ronan M., Kadiyala, Ajay Kumar, McCarthy, Michael A., McCarthy, Conor T.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.03.2020
• Subjects: Adhesion; Joints/joining; Metal to thermoplastic composite bonding; Surface treatment; Joints/joining; Metal to thermoplastic composite bonding; Adhesion; Surface treatment
• ISSN: 1359-8368; 1879-1069
• DOI: 10.1016/j.compositesb.2020.107765

Light-weighting of transportation structures necessitates multi-material design employing composites and aluminium, with thermoplastic composites being of increasing interest to the industry. Adhesive bonding is a viable solution for joining dissimilar materials, but joint performance can be considerably affected by surface preparation. In this paper, alumina grit-blasting is investigated as a surface preparation technique for thermoplastic-matrix composites to be bonded to aluminium alloys. Grit-blasting is performed on composite adherends for varying durations, and the resulting chemical and morphological modifications are analysed using goniometry, profilometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Adhesively-bonded single-lap joints are tested at quasi-static and dynamic (0.5 m/s) loading rates, and fractography analysis is performed at macro and micro scales. It is found that high lap shear strength and work-to-failure can be achieved through optimisation of the grit-blasting parameters. The optimised process produces a composite surface with plasticised matrix, minimal fibre exposure, and favourable surface chemistry for adhesive bonding. Grit-blasting can thus be a simple, yet effective surface preparation technique for composites to be bonded to aluminium.