This study is part of an ongoing effort to develop high performance CoNiCrAlY bond coats by means of cold gas dynamic spraying in order to have complete control of bond coat microstructure. As such, the objective of the work presented in this paper is to perform a detailed analysis of cold sprayed CoNiCrAlY layers to assess any changes in microstructure, relative to the original feedstock powder, that may have occurred during layer build-up and compaction. Based on SEM, TEM, and XRD examination results, it is shown that, contrary to the generally accepted theory, important microstructural changes occur during the cold spray deposition process. In the coating samples examined, investigators observed evidence of grain refinement in the CoNiCr γ-phase matrix and partial dissolution of NiAl β-phase precipitates. These changes are a result of severe plastic deformation due to the high-velocity impact of sprayed particles.

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