1. Using the 3-point bending method to study failure initiation in epoxide-aluminum joints
- Author
-
Maëlenn Aufray, Pierre Chalandon, Michel Nardin, Dominique Poquillon, Jean-Baptiste Sauvage, Jean-Pierre Jeandrau, Centre Technique des Industries Mécaniques - CETIM (FRANCE), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université de Haute Alsace - UHA (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS), and CEntre Technique des Industries Mécaniques - Cetim (FRANCE)
- Subjects
Materials science ,Polymers and Plastics ,Three point flexural test ,General Chemical Engineering ,Matériaux ,Interfaces ,02 engineering and technology ,Substrate (printing) ,Bending ,engineering.material ,Biomaterials ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Coating ,Epoxides ,Destructive testing ,Composite material ,030206 dentistry ,Epoxy ,021001 nanoscience & nanotechnology ,Silane ,3-point bending test ,chemistry ,[SPI.MECA.STRU]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Structural mechanics [physics.class-ph] ,visual_art ,visual_art.visual_art_medium ,engineering ,Adhesive ,Mécanique des matériaux ,0210 nano-technology ,Aluminum and alloys - Abstract
International audience; The increasing use of adhesives in industry has boosted the search for tests which allow the adherence level to be defined. These tests, depending on the type of load, examine different stresses, failure modes and mixed modes. Furthermore, these tests can be focused either on initiation or propagation of adhesive failure. The subject of this study is the initiation of adhesive failure. The initiation of failure can be determined with the 3-point bending test. Trials of 3-point bending tests were conducted on an aluminum 2024 substrate, with two different thicknesses, in order to understand the impact of the adherend thickness. The aluminum substrate received different types of surface pre-treatment: acetone cleaning, hydrochloric acid etching or aminopropyltriethoxysilane coating. Two adhesives were used: the first one was a mixture of epoxy pre-polymer DGEBA and DETA amine, whereas the second was a commercially formulated adhesive, ELECOLIT 6604. The initiation of adhesive failure was obtained by 3-point bending test and verified with SEM analysis. The failure loads measured enabled the effect of surface treatment on adhesive failure to be revealed: the results indicate that the surface treatment with silane is the most efficient in comparison to hydrochloric acid etching and of course to the simple acetone degreasing. It was assumed that the scatter of the results obtained for each series is due to the variation of the “intrinsic” adherence between the adhesive and the substrate. Furthermore, it was noted that the failure loads for different substrate thicknesses cannot be compared due to the effect of the thickness: it was therefore not possible to simply compare results obtained for different thicknesses of the same substrate for a given substrate-adhesive system. The energy approach proposed in this study makes it possible. The energy requested to initiate the adhesive failure for a given system can then be known, whatever the initial geometry of the 3-point bending test is. However, it was also shown that the thickness of the substrate must be correctly chosen. A thick substrate increases the dispersion and a thin substrate may induce local unwelcome plastic strain. In conclusion, this study allows to define an energy criteria for adhesives failure initiation.
- Published
- 2017