Title

Factors governing the mechanical behaviour of CrSiN coatings: Combined nanoindentation testing and transmission electron microscopy

Document Type

Journal Article

Faculty

Faculty of Computing, Health and Science

School

School of Engineering

RAS ID

15194

Comments

This article was originally published as: Wo, P., Munroe, P., Li, Z., Jiang, Z., Xie, Z. , Zhou, Z. , & Li, K. (2012). Factors governing the mechanical behaviour of CrSiN coatings: Combined nanoindentation testing and transmission electron microscopy. Materials Science and Engineering A, 534(0), 297-308.

Abstract

A direct link between the microstructure and mechanical properties of CrSiN coatings with varying Si contents was established by examining their microstructural evolution and deformation behaviour, enabled by cross-sectional transmission electron microscopy. A transformation from a columnar-grained structure, in the binary compound, to a nanocomposite structure, consisting of CrN nanocrystallites embedded in an amorphous matrix, was observed in the coating having a Si content of 28.5at.%. The columnar-structured coatings were observed to deform by grain boundary shear sliding, whilst cracks occurred in nanocomposite coatings. Moreover, the coating having a Si content of 14.3at.% exhibited the highest hardness as a result of grain boundary strengthening facilitated by Si 3N 4 segregation, together with solid solution strengthening of Si in CrN, the Hall-Petch effect for the finer CrN grains and a high compressive residual stress. A further increase of Si content to 28.5at.% led to a reduction in hardness due to the high volume fraction of the amorphous phase, together with the presence of cracks in the as-deposited coating. The findings provide deeper insight into the origin of the mechanical behaviour of CrSiN coatings.

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