Publications and Research
Document Type
Article
Publication Date
11-21-2024
Abstract
This study deals with the long-running challenge of joining similar and dissimilar materials using composite-to-composite and composite-to-metal joints. This research was conducted to evaluate the effects of surface morphology andsurfacetreatments onthemechanicalperformanceofadhesively bonded joints used for the aircraft industry. A two-segment, commercially available, toughened epoxy was chosen as the adhesive. Unidirectional carbon fiber prepreg and aluminum 2021-T3 alloys were chosen for the composite and metal panels, respectively. Surface treatment of the metal included corrosion elimination followed by a passive surface coating of Alodine®. A combination of surface treatment methods was used for the composite and metal specimens, including detergent cleaning, plasma exposure, and sandblasting. The shear strength of the single-lap adhesive joint was evaluated according to the ASTM D1002. Ultraviolet (UV) and plasma exposure effects were studied by measuring the water contact angles. The test results showed that the aluminum adherent treated with sandblasting, detergent, and UV irradiation resulted in the strongest adhesive bonding of the composite-to-composite panels, while the composite-to-metal sample cleaned only with detergent Citation: Paranjpe, N.; Uddin, M.N.; Rahman, A.S.; Asmatulu, R. Effects of Surface Treatment on Adhesive Performance of Composite to-Composite and Composite-to-Metal Joints. Processes 2024, 12, 2623. https://doi.org/ 10.3390/pr12122623 Academic Editor: Anil K. Bhowmick Received: 30 October 2024 Revised: 15 November 2024 Accepted: 19 November 2024 Published: 21 November 2024 Copyright: © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). resulted in the least bonding strength. The failure strain of the composite-to-composite bonding was reduced by approximately 50% with only sandblasting. However, extended treatment did not introduce additional brittleness in the adhesive joint. The bonding strength of the composite-to composite panel improved by approximately 35% with plasma treatment alone because of the better surface functionalization and bonding strength. In the composite-to-aluminum bonding process, exposing the aluminum surface to UV resulted in 30% more joint strength compared to the Alodine® coating, which suggests the origination of higher orders of magnitude of covalent groups from the surface. A comparison with published results found that the joint strengths in both similar and dissimilar specimens are higher than most other results. Detailed observations and surface analysis studies showed that the composite-to-composite bonding mainly failed due to adhesive and cohesive failures; however, failure of the composite-to-aluminum bonding was heterogeneous, where adhesive failure occurred on the aluminum side and substrate failure occurred on the composite side.
Comments
This article was originally published in Processes, available at https://doi.org/10.3390/pr12122623
This work is distributed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).