Title: Improving the Peel Strength of Amorphous Metal Foil to Aerospace-Grade Structural Adhesive

Authors: Rose Roberts, Matthew Nichols, Elizabeth Kidd, Flora Mechentel, Giles Dillingham

DOI: 10.33599/nasampe/s.21.0524

Abstract: Amorphous metal applications in aerospace have grown with the continuous improvement of production methods. These bulk metallic glass materials, often produced as a foil, generally exhibit stronger mechanical properties and corrosion resistance compared to crystalline metal. An amorphous metal foil was chosen as the best material for a particular satellite component, bonded in place using an aerospace-grade structural adhesive. However, previous work has shown that amorphous metal foils exhibit poor peel strength when bonded with structural adhesives. This paper discusses the mechanics of peel testing and the inherent limitations imposed by the amorphous metal foil properties; peel strength was maximized within these limitations by optimization of surface preparation techniques until cohesive failure in a thin film of adhesive was obtained as shown by surface analysis. The process was further developed for building satellite components on a larger scale.

References: 1. “Developing Starshade Technology to Image Earthsized Exoplaents around Neighboring Stars.” United States. National Aeronautics and Space Administration. 2017 Science Mission Directorate: Technology Highlights Washington, D.C.: GPO, 2017. 2. Steeves, John; Martin, Stefan; Webb, David; Lisman, Douglas; Shaklan, Stuart. “Precision Optical Edges for a Starshade External Occulter.” Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II. Edinburgh, UK, 22 July 2016. Proc. SPIE 9912. Paper. DOI: 10.1117/12.2233409 3. Diegle, Ronald B. “Chemical Properties of Metallic Glasses.” Journal of Non-Crystalline Solids 61&62 (1984): 601-612. 4. Jaray-Zadeh, M., Kumar, G. P., Branicio, P. S., Seifi, M., Lewandowski, J. J., and Cui, F. “A Critical Review on Metallic Glasses as Structural Materials for Cardiovascular Stent Applications.” Journal of Functional Biomaterials 9(19) (2018). DOI:10.3390/jfb9010019 5. Our previous SAMPE paper 6. Abbott, Steven. Adhesion Science: Principles and Practice. Lancaster, Pennsylvania: DEStech Publications, Inc., 2015. 7. Li, Q.; Batra, R. C.; Graham, I.; Dillard, D. A. “Examining T-peel specimen bond length effects: Experimental and numerical explorations of transitions to steady-state debonding.” International Journal of Solids and Structures 180-181 (2019): 72-83. DOI: 10.1016/j.ijsolstr.2019.07.012 8. Bikerman, J.J. “Theory of Peeling through a Hookean Solid.” Journal of Applied Physics 28 (1957): 1484-1485. DOI: 10.1063/1.1722682 9. Kaelble, D. H. “Theory and Analysis of Peel Adhesion: Bond Stresses and Distributions.” Transactions of the Society of Rheology 4 (1960): 45-73. DOI: 10.1122/1.548868 10. ASTM Standard D1002-10, “Apparent Shear Strength of Single-Lap-Joint Adhesively Bonded Metal Specimens by Tension Loading (Metal-to-Metal)” ASTM International, West Conshohocken, PA, 2019, DOI: 10.1520/D1002-10, www.astm.org. 11. “Technical Process Bulletin: Loctite EA 9394 Aero Epoxy Paste Adhesive.” Henkel (2013). 12. “Technical Process Bulletin: Loctite EA 9360 Aero Epoxy Paste Adhesive.” Henkel (2013). 13. ASTM Standard D3167-10, “Standard Test Method for Floating Roller Peel Resistance of Adhesives” ASTM International, West Conshohocken, PA, 2017, DOI: 10.1520/D3167-10R17, www.astm.org. 14. ASTM Standard E4-20, “Standard Practices for Force Verification of Testing Machines” ASTM International, West Conshohocken, PA, 2020, DOI:10.1520/E0004-20, www.astm.org. 15. Wisanrakkit, G. and Gillham, J. K. “Continuous heating transformation (CHT) cure diagram of an aromatic amine/epoxy system at constant heating rates.” Journal of Applied Polymer Science 42(9) (1991): 2453-2463. DOI: 10.1002/app.1991.070420911 16. Hickey, C. M. D., and Bickerton, S. “Cure kinetics and rheology characterisation and modelling of ambient temperature curing epoxy resins for resin infusion/VARTM and wet layup applications.” Journal of Materials Science 48 (2013): 690-701. DOI: 10.1007/s10853-012-6781-8 17. McCray, D. B., Smith, J. A., Storage, K. M., Ripberger, E. R., Shouse, M. D., and Mazza, J. J. “Nonmetallic Materials Supportability: The Evaluation of Two-Part Epoxy Paste Adhesives for Repair Bonding of Aluminum Alloys.” Air Force Research Laboratory Interim Report (2011): AFRL-RX-WP-TR-2013-0054

Conference: SAMPE NEXUS 2021

Publication Date: 2021/06/29

SKU: TP21-0000000524

Pages: 10

Price: FREE