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Near-field acoustical imaging using lateral bending mode of atomic force microscope cantilevers

Applications to fracture mechanics of NC-zirconia
 
: Caron, A.; Rabe, U.; Rödel, J.; Arnold, W.

:
Postprint urn:nbn:de:0011-n-556736 (191 KByte PDF)
MD5 Fingerprint: 3e6e96d5f9cb6d8fc16e11df570e4227
The original publication is available at springerlink.com
Erstellt am: 9.7.2010


André, M.P.:
Acoustical Imaging. Vol.28. Proceedings of the 28th International Symposium on Acoustical Imaging 2005 : March 20 - 23, 2005, San Diego, California
Berlin: Springer, 2007
ISBN: 1-4020-5720-2
ISBN: 978-1-4020-5720-5
ISBN: 978-1-4020-5721-2
S.31-41
International Symposium on Acoustical Imaging <28, 2005, San Diego/Calif.>
Englisch
Konferenzbeitrag, Elektronische Publikation
Fraunhofer IZFP ()
atomic force microscopy; Atomic Force Acoustic Microscopy; scanning acoustic microscopy; crack-tip toughness; process zone

Abstract
Scanning probe microscopy techniques enable one to investigate surface properties such as contact stiffness and friction between the probe tip and a sample with nm resolution. So far the bending and the torsional eigenmodes of an atomic force microscope cantilever have been used to image variations of elasticity and shear elasticity, respectively. Such images are near-field images with the resolution given by the contact radius typically between 10 nm and a cantilever oscillating in the width direction and parallel to the sample surface can also be used for imaging. Additional to the dominant in-plane component of the oscillation, the lateral modes exhibit a vertical component as well, provided there is an asymmetry in the cross-section of the cantilever or in its suspension. The out-of-plane deflection renders the lateral modes detectable by the optical position sensors used in atomic force microscopes. We studied cracks which were generated by Vickers indents, in submicro- and nanocrystalline ZrO2. Images of the lateral contact stiffness were obtained by vibrating the cantilever close to a contactresonance frequency. A change in contact stiffness causes a shift of the resonant frequency and hence a change of the cantilever vibration amplitude. The lateral contact-stiffness images close to the crack faces display a contrast that we attribute to altered elastic properties indicating a process zone. This could be caused by a stress-induced phase transformation during crack propagation.
Using the contact mode of an atomic force microscope, we measured the crackopening displacement as a function of distance from the crack tip, and we determined the crack-tip toughness Ktip. Furthermore, K1c was inferred from the length of radial cracks of Vickers indents that were measured using classical scanning acoustic microscopy.

: http://publica.fraunhofer.de/dokumente/N-55673.html