Title

Scratch-Induced Deformation And Residual Stress In A Zirconium Diboride-Silicon Carbide Composite

Abstract

A ZrB2-5wt%SiC composite was produced employing a plasma pressure compaction technique at a temperature of 1750°C and at a pressure of 43 MPa over a short consolidation period of only 5 min. The resulting compact had a sintered density above 96% of theoretical density. Scratch experiments were conducted on the composite in the load range of 50 to 250 mN using a Berkovich nanoindenter. Microstructural analysis of the scratch grooves revealed that the grooves consisted of several sets of slip lines oriented at random angles to the scratch direction and transgranular microcracks, oriented orthogonal to the scratch direction. Also, ZrB2 grain-boundary fracture and interfacial cracking between ZrB2 matrix and SiC particles were observed at higher scratch loads. An analytical model based on combined Boussinesq field and Cerruti field solutions was used to rationalize the formation of slip lines and orthogonal microcracks. It was postulated from the mechanistic analysis that the maximum shear stress which occurs ahead of the indenter tip during the scratch process caused the slip lines where as the principal tensile stress in the wake of the indenter caused the microcracking perpendicular to the scratch direction. This postulation was later verified by the observation of slip lines ahead of the scratch groove at the exit-end. Micro-Raman spectroscopy was employed to measure the scratch-induced residual stress within the SiC particles. The Raman spectra indicated a gradual increase in the residual stress with scratch load.

Publication Date

3-27-2009

Publication Title

Ceramic Engineering and Science Proceedings

Volume

29

Issue

2

Number of Pages

51-63

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

Socpus ID

62849103149 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/62849103149

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