Direct evidence for compressive elastic strain at ground surfaces of nanocomposite ceramics

Tanner, B.K.; Wu, H.Z.; Roberts, S.G.

Abstract

High-resolution grazing incidence x-ray powder diffraction has been used to provide direct evidence for the existence of a uniform compressive strain close to the surface of ground alumina/SiC nanocomposites. No such strain is found in ground surfaces of single-phase alumina or polished surfaces of nanocomposite. The strain in the ground nanocomposite is found to be perpendicular to the grinding direction and disappears on annealing at 1250 °C. Such a compressive stress provides a mechanism for enhancing the strength of the nanocomposite, by opposing any tensile loading tending to open surface flaws. The origin of the stresses probably lies in the enhanced grain boundary strength in the nanocomposite alumina–silicon carbide compared to alumina.

Citation

Tanner, B., Wu, H., & Roberts, S. (2005). Direct evidence for compressive elastic strain at ground surfaces of nanocomposite ceramics. Applied Physics Letters, 86(6), https://doi.org/10.1063/1.1862754

• Journal Article Type: Article
• Publication Date: Feb 7, 2005
• Deposit Date: Dec 4, 2006
• Publicly Available Date: Apr 21, 2011
• Journal: Applied Physics Letters
• Print ISSN: 0003-6951
• Electronic ISSN: 1077-3118
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 86
• Issue: 6
• DOI: https://doi.org/10.1063/1.1862754
• Keywords: Alumina, Silicon compounds, Nanocomposites, Ceramics, Annealing, Grain boundaries, Internal stresses, Micromechanics, Compressive strength, Surface cracks, Grinding, Elasticity, X-ray diffraction.