Journal ArticleDOI
The anisotropy of surface deformation of sapphire : continuous indentation of triangular indenter
Roman Nowak,M. Sakai +1 more
TLDR
In this article, an attempt is made to explain the anisotropy of indentation-induced deformation and fracture of sapphire for different crystallographic planes indented by a variously oriented triangular diamond indenter.Abstract:
An attempt is made to explain the anisotropy of indentation-induced deformation and fracture of sapphire for different crystallographic planes indented by a variously oriented triangular diamond indenter. The anisotropic surface deformation and fracture of the indented crystal are discussed using a new effective resolved shear stress (ERSS) model. The patterns of the surface traces of twins and cracks are predicted on the basis of the ERSS-calculations performed for all the slip and twinning systems which are potentially activated during room temperature indentation. The theoretical prediction of the ERSS model agrees very well with the observed hardness anisotropy. The present work is the first application of the continuous indentation test to the anisotropic surface deformation of single crystals.read more
Citations
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Journal ArticleDOI
3-D raman spectroscopy measurements of the symmetry of residual stress fields in plastically deformed sapphire crystals
TL;DR: In this paper, the authors investigated the 3D residual stress field around a microindent using confocal Raman microscopy with a lateral resolution of 300 nm and a depth resolution of 600 nm.
Journal ArticleDOI
Acoustic emission monitoring of the earliest stages of contact-induced plasticity in sapphire
TL;DR: In this paper, an acoustic emission (AE) sensor integrated into an indenter tip provided a unique insight into the mechanisms of the initial stages of plasticity for four different sapphire single crystal surface orientations.
Journal ArticleDOI
Plasticity and fracture of sapphire at room temperature: Load-controlled microcompression of four different orientations
TL;DR: In this paper, the mechanical behavior and deformation mechanisms in sapphire (Al 2 O 3 ) were studied using micro-pillar compression experiments performed in situ in a scanning electron microscope (SEM) at room temperature.
Journal ArticleDOI
Static and dynamic indentation response of basal and prism plane sapphire
Edward J. Haney,Ghatu Subhash +1 more
TL;DR: In this paper, both static and dynamic indentations of sapphire along the c[0, 0,0,1] and a [ 1 1 2 ¯ 0 ] crystallographic axes are compared to determine the loading rate dependence on its mechanical response, and the results indicate that dynamic hardness increases by 10% and 12% over static hardness for basal and prism planes, respectively.
Journal ArticleDOI
The effect of abrasive hardness on the chemical-assisted polishing of (0001) plane sapphire
TL;DR: A series of abrasives with various hardness values including monocrystalline and polycrystalline diamond, α- and γ-alumina, zirconia, ceria, and silica were used to examine the concept of chemical-assisted polishing for finishing the (0001), c-plane (basal plane), of sapphire as mentioned in this paper.
References
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Book
Theory of elasticity
TL;DR: The theory of the slipline field is used in this article to solve the problem of stable and non-stressed problems in plane strains in a plane-strain scenario.
Book
Theory of elasticity
TL;DR: The equilibrium of rods and plates Elastic waves Dislocations Thermal conduction and viscosity in solids Mechanics of liquid crystals Index as discussed by the authors The equilibrium of rod and plate elastic waves Elastic waves
Book
Fracture Mechanics of Ceramics
TL;DR: In this article, a linear-elastic fracture mechanics can be applied to describe the failure behavior of small flaws in ceramic materials, which is caused by the extension of small faults.
Journal ArticleDOI
Measurement of thin film mechanical properties using nanoindentation
George M. Pharr,Warren C. Oliver +1 more
TL;DR: Nanoindentation has become one of the most widely used techniques for measuring the mechanical properties of thin films as discussed by the authors, and has been shown to be useful in the study of optical coatings, hard coatings and materials modified by ion implantation and laser treatment.