Neutron Diffraction Study of Macrostress and Microstress in Al-Al2O3-Based Corrosion Protection Coating Obtained by Cold Spray (Dynamic Metallization)
V. Luzin, P. Spiridonov, K. Spencer, Thomas H. Gnaupel-Herold
Protective coatings based on an Al/Al2O3 metal matrix composite (MMC) were sprayed using Dynamic Metallisation (DM), a low-pressure cold spray variant. A series of samples approximately 1mm in thickness were sprayed with changing parameters of the spraying process (temperature, velocity) and the composition of the feedstock powders (Al, Zn, Al2O3). This resulted in MMCs of different phase compositions and slightly different physical conditions of coating formation. the through-thickness residual stresses that accumulate in coatings during the spray process were studied using neutron diffraction in all phases compressive, which is in good agreement with the date on residual stress observed in other cold spray coatings, accumulating as a result of the peening process. However, due to the slightly elevated spray temperature characteristic of DM in comparison to other cold spray variants, thermal stresses are also present and play an equally important role in the accumulation of residual stress in each phase. Because of the multi-phase composition and thermal mismatch between the metal and ceramic components of the MMC, inter-phase microstresses also accumulate. A micro-mechanical explanation of the observed tensile microstress in Al/Zn vs. compressive stress in Al2O3 is proposed.
, Spiridonov, P.
, Spencer, K.
and Gnaupel-Herold, T.
Neutron Diffraction Study of Macrostress and Microstress in Al-Al<sub>2</sub>O<sub>3</sub>-Based Corrosion Protection Coating Obtained by Cold Spray (Dynamic Metallization), Journal of Thermal Spray Technology
(Accessed July 3, 2022)