Neutron Diffraction Study of Macrostress and Microstress in Al-Al 2 O 3 -Based Corrosion Protection Coating Obtained by
- PDF / 1,087,397 Bytes
- 18 Pages / 595.276 x 790.866 pts Page_size
- 58 Downloads / 159 Views
PEER REVIEWED
Neutron Diffraction Study of Macrostress and Microstress in AlAl2O3-Based Corrosion Protection Coating Obtained by Cold Spray (Dynamic Metallization) V. Luzin1,2 • P. Spiridonov3 • K. Spencer4 • T. Gnaupel-Herold5
Submitted: 13 November 2019 / in revised form: 21 June 2020 ASM International 2020
Abstract Protective coatings based on an Al-Al2O3 metal matrix composite (MMC) were sprayed using dynamic metallization (DM), a low-pressure cold spray variant. A series of samples approximately 1 mm in thickness were sprayed using different spray process parameters (temperature, velocity) and different feedstock powder compositions (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 comprising the MMCs. The overall residual stress in the coating (macrostress) was compressive, which is in good agreement with the data on residual stress observed in other cold spray coatings, accumulating as a result of the peening process. However,
This article is part of a special topical focus in the Journal of Thermal Spray Technology on Advanced Residual Stress Analysis in Thermal Spray and Cold Spray Processes. This issue was organized by Dr. Vladimir Luzin, Australian Centre for Neutron Scattering; Dr. Seiji Kuroda, National Institute of Materials Science; Dr. Shuo Yin, Trinity College Dublin; and Dr. Andrew Ang, Swinburne University of Technology. & V. Luzin [email protected]
due to the slightly elevated spray temperature characteristic of DM in comparison with 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 versus compressive stress in Al2O3 is proposed. Keywords cold spray coatings residual stress microstress neutron diffraction List of Symbols rM rl ral ratot f r E Ejj ; E? da djj ; d?
1
Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2232, Australia
2
School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
d0
3
InnovEco Australia, Enfield, SA 5085, Australia
ðhklÞ
4
BHP Billiton, BMA Coal, 71 Eagle St, Brisbane, QLD 4000, Australia
2hðhklÞ
5
NIST Center for Neutron Research, Gaithersburg, MD 20899, USA
Macrostress (tensor) Microstress (tensor) Microstress of phase a Total (phase) stress of phase a Volume fraction of hard particle (inclusion) phase Stress averaged over the gauge volume Young’s modulus Young’s modulus for the in-plane (||) and normal (?) directions in coatings d-spacing of phase a Measured d-spacing in-plane (||) and normal (?) directions Reference (macrostr
Data Loading...
