Title: Heat Treatment of AA2024 Powders for Enhanced Solid State Structural Repairs Via Cold Spray Deposition

Authors: William A. Story, Tian Liu, and Luke N. Brewer

DOI: 10.33599/nasampe/s.19.1425

Abstract: This presentation will describe new results on the heat treatment of AA2024 feedstock powder for cold spray deposition. Cold spray deposition is being developed as a means for repairing corrosion damage in high strength aluminum aircraft components. The microstructure of gas atomized powders is not optimized for spray characteristics or mechanical properties. We have applied a new heat treatment approach to solutionize these powders, thus removing the intermetallic network. Powders were solutionized for 75 minutes at 498°C in a rotary furnace and then quenched. For comparison, other powders were intentionally aged at 150°C and 225°C for 20 hours. All of these powders were sprayed onto AA2024 substrates using the VRC Metal Systems generation III cold spray system with helium as the spray gas. The mass deposition efficiency improved from 46% to 75% for the solutionized powders. The 150°C/20hour sample showed a reduction in deposition efficiency to 38%, while the 225°C/20hour sample increased to 61%. Microscopy of the particles showed that the solution treatment removed the majority of the S phase intermetallic network, while the overaging treatments did not. S’ precipitates were not observed in coatings produced with feedstock powder but were present after natural aging for coatings produced with solutionized powders.

References: 1. Villafuerte, Julio, Modern Cold Spray: Materials, Process, and Applications, Switzerland, Springer International Publishing, 2015. 10.1007/978-3-319-16772-5 2. R. Jones, L. Molent, S. Barter, N. Matthews, D. Tamboli, Supersonic particle deposition as a means for enhancing the structural integrity of aircraft structures, International Journal of Fatigue 68 (2014) 260-268. 3. Prasad, H., Henein, H., and Conlon, K., “Quantification Of Microsegregation During Rapid Solidification of Al-Cu Powders”, Metallurgical and Materials Transactions A 37 (2006): 1589-1596. https://doi.org/10.1007/s11661-006-0102-2 4. Liu, T., Leazer, J.D., Menon, S.K., Brewer, L.N., “Microstructural Analysis of Gas Atomized Al-Cu Alloy Feedstock Powders for Cold Spray Deposition”, Surface and Coatings Technology 350 (2018): 621-632 https://doi.org/10.1016/j.surfcoat.2018.07.006 5. She, Y., Nardi, A.T. Klecka, M.A. “High Temperature Fluidized Bed for Powder Treatment”, US Patent 9,555,474 B2, (2017) 6. Rokni, M., Nardi, A., Champagne, V., and Nutt, S. “Effects of Preprocessing on Multi-Direction Properties of Aluminum Alloy Cold-Spray Deposits”, Journal of Thermal Spray Technology 27 (2018): 818-826. https://doi.org/10.1007/s11666-018-0723-1 7. Sabard, A., de Villiers Lovelock, H., and Hussain, T., “Microstructural Evolution in Solution Heat Treatment of Gas-Atomized Al Alloy (7075) Powder for Cold Spray”, Journal of Thermal Spray Technology 27 (2017): 145-158. https://doi.org/10.1007/s11666-017-0662-2 8. Story, W.A. and Brewer, L.N. “Heat Treatment of Gas-Atomized Powders for Cold Spray Deposition”, Metallurgical and Materials Transactions A 49 (2018): 446-449. https://doi.org/10.1007/s11661-017-4428-8 9. Liu, T., Story, W.A. and Brewer, L.N. “Effect of Heat Treatment on the Al-Cu Feedstock Powers for Cold Spray Deposition” Submitted to Metallurgical and Materials Transactions A (2018). 10. Staley, J.T., Axter, S.E., Barker, L.J., Hull, J.H., Leholm, R.B., and Wilson, P.C. “Heat Treating of Aluminum Alloys”, ASM Metals Handbook Ed. W.H. Cubberly, Vol. 4 Heat Treat., 9th ed., Metals Park, OH: American Society for Metals, (1981): 707–709. 11. Wang, S.C. and Starink, M.J. “Two Types of S Phase Precipitates in Al – Cu – Mg Alloys”, Acta Materialia 55 (2007) 933–941. doi:10.1016/j.actamat.2006.09.015. 12. Biswas, A., Siegel, D.J., Wolverton, C., Seidman, D.N. “Precipitates in Al – Cu Alloys Revisited : Atom-probe Tomographic Experiments and First-Principles Calculations of Compositional Evolution and Interfacial Segregation”, Acta Materialia 59 (2011): 6187–6204. doi:10.1016/j.actamat.2011.06.036.

Conference: SAMPE 2019 - Charlotte, NC

Publication Date: 2019/05/20

SKU: TP19--1425

Pages: 11

Price: FREE