Experimental evaluation of interfacial adhesion strength of cold sprayed Ti-6Al-4V thick coatings using an adhesive-free test method

Dibakor Boruah, Ben Robinson, Tyler London, Huan Wu, Heidi de Villiers-Lovelock, Philip McNutt, Matthew Doré, Xiang Zhang

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)
27 Downloads (Pure)

Abstract

Cold spray (CS) is a rapidly growing solid-state additive material deposition technique often used for repair of high-value metallic components. This study aims at evaluating the interfacial adhesion strength of cold sprayed Ti-6Al-4V (Ti-64) coatings deposited onto Ti-64 substrates for repair applications. An adhesive-free test method, referred as modified Collar-Pin Pull-off Test was developed based on Sharivker's (1967) original design, in order to overcome the limitations of existing test approaches (both adhesive-based and adhesive-free). This method was designed to allow measurement of adhesion strength of high strength coatings such as CS Ti-64, where adhesion strength is higher than 70–90 MPa. A parametric study was performed to assess the effect of coating thickness, scanning speed, track spacing, toolpath pattern, and substrate surface preparation on the coating adhesion strength. A finite element model was also used to evaluate the stress distribution during the pull-off test, and to check the validity of the proposed test method. The proposed adhesive-free test method was found to be capable of measuring coatings with adhesion strengths beyond the upper limit of conventional adhesive-based methods such as ASTM C633. Among the investigated cases, the highest value of coating adhesion strength was measured around 122 MPa, in the case of CS Ti-64 deposited on ground Ti-64 substrates.

Original languageEnglish
Article number125130
Number of pages15
JournalSurface and Coatings Technology
Volume381
Early online date6 Nov 2019
DOIs
Publication statusPublished - 15 Jan 2020

Bibliographical note

NOTICE: this is the author’s version of a work that was accepted for publication in Surface and Coatings Technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Surface and Coatings Technology (2019)
https://dx.doi.org/10.1016/j.surfcoat.2019.125130
© 2019, Elsevier. Licensed under the Creative Commons AttributionNonCommercial-NoDerivatives 4.0 International
http://creativecommons.org/licenses/by-nc-nd/4.0/

Funder

This publication was made possible by the sponsorship and support of the Lloyd's Register Foundation (grant number DB012017COV ), . Coventry University has also contributed to the PhD studentship (grant number 7486157 ). This work was partially funded by the Industrial Members of TWI Ltd. through the Core Research Programme (grant number 30643).

Keywords

  • Adhesion strength
  • Coatings
  • Cold spray
  • Repairs
  • Thermal spray
  • Ti-6Al-4V
  • Additive manufacturing

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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