Investigation of strain-hardening characteristics of cold-sprayed Al–Al₂O₃ coatings: a combined nanoindentation and expanding cavity models approach

ABSTRACT

The paper has taken a fundamental approach to study the nano-scale deformation behavior of Al-Al2O3 cermet coatings deposited by low-pressure cold spraying (LPCS) on AZ31 magnesium and Al6056 lightweight alloy substrates. Coating microstructural characteristics were first evaluated and correlated with LPCS process parameters using metallurgical characterization techniques: SEM, 3D optical profilometry, and XRD, followed by their microhardness and wear depth measurements and comparing with uncoated substrates under three-body abrasion wear. These properties were analyzed/mapped against probable deformation scenarios for nano-scale yield strength determination using the combined experimental nanoindentation load-depth curve method and computational expanding cavity models (ECMs). Obtained yield strength with key coating parameters like hardness and Young’s modulus were taken for modeling and simulation of strain-hardening effect under a peak loading of 165 mN in ABAQUS finite element (FE). Results from both combined experimental/computational and FE approaches indicate a progressive elasto-plastic mode being the dominating coating deformation mechanism with a strain hardening exponent of 0.15, under the studied loads.

KEYWORDS:

• Al–Al₂O₃ cermet
• low-pressure cold spray
• nanoindentation
• expanding cavity models
• FE simulation

Acknowledgements

The microscopic characterization work was supported by the Microscopy and Microanalysis Facility at the University of New Brunswick.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability

The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study.

Additional information

Funding

The authors are thankful for the funding provided by the Natural Sciences and Engineering Research Council of Canada (RGPIN-2018-04440).