Microscale fracture mechanisms of a Cr3C2-NiCr HVOF coating

Thermal spray coatings, often composed of heterogeneous, multiphase microstructures, may, consequently, exhibit complex fracture behavior. For such coating structures, conventional mechanical evaluation methods fail to isolate the contribution of microstructural features to the overall fracture beha...

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Bibliographic Details
Published inMaterials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 688; pp. 62 - 69
Main Authors Robertson, Andrew L., White, Ken W.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 14.03.2017
Subjects
Composites
Fracture
Interfaces
Micromechanics
Micromechanics
Interfaces
Composites
Fracture
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Summary:Thermal spray coatings, often composed of heterogeneous, multiphase microstructures, may, consequently, exhibit complex fracture behavior. For such coating structures, conventional mechanical evaluation methods fail to isolate the contribution of microstructural features to the overall fracture behavior. For this reason, this study employed focused ion beam machined (FIB) microcantilever beams and FIB sectioning methods to study the fracture mechanisms important at the scale of the heterogeneous Cr3C2-NiCr thermal spray coating. We found three fracture modes, namely, intergranular matrix fracture, matrix/carbide interfacial fracture, and carbide cleavage. By comparison, microindentation-induced cracks, the frequency of crack deflection around carbides is significantly more prevalent at this much larger crack dimension. This mechanistic variation provides some insight into the specific role and limitations of the microcantilever beam technique for fracture characterization of composite microstructures.
ISSN:0921-5093
1873-4936
DOI:10.1016/j.msea.2017.01.097