Characterisation of the Residual Stresses in HVOF WC-Co Coatings and Substrates

Abstract:

Residual strains and stresses associated with the processing steps of the industrial high-velocity oxygen-fuel (HVOF) thermal spray technique, was non-destructively characterised in both the coatings and substrates. A range of substrates, having coefficients of thermal expansion different to that of the as-coated WC-Co material, have been considered to assess the potential role of the thermal misfit associated with the coating procedure. Surface and depth resolved studies of the in-plane and normal components of residual strains have been investigated by exploiting the penetrating capabilities of high energy synchrotron X-rays in conjunction with micron sized gauge volumes to enable strain gradient determination with high positional resolution. Results reveal the presence of large residual strain/stress mismatches at the interface region in all the substrate materials, whereas the strains/stresses in the as-coated material are small, seemingly independent of the substrate material. The different contributions due to the HVOF process are qualitatively assessed in terms of an eigenstrains (plastic deformation) approach.

• Periodical: Materials Science Forum (Volumes 768-769)
• Pages: 280-285
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.768-769.280
• Online since: September 2013
• Authors: Andrew M. Venter, Oluseyi Philip Oladijo, L.A. Cornish, Natasha Sacks
• Keywords: Depth Resolved Strain/Stress, Eigenstrain, HVOF Coated Substrates, WC-Co Spraying Coating

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