Dresden 2009 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 35: Poster Session II
MM 35.12: Poster
Wednesday, March 25, 2009, 16:30–18:30, P4
Study of local and global elastic properties by atomic force acoustic microscopy and ultrasonic spectroscopy of a metallic glass — •Hannes Wagner1, Stefan Küchemann1, Christian Vree1, Walter Arnold2, and Konrad Samwer1 — 1I.Physikalisches Institut, Universität Göttingen — 2Permanent address: Department of Materials and Technology, Saarland University, Saarbrücken
We are looking for local variations of the indentation modulus of a metallic glass. To visualize this effect we use an atomic force acoustic microscope, where the cantilever of an atomic force microscope is excited by a transducer at ultrasonic frequencies while the sensor tip is contacting the sample surface. From various resonance frequencies of this contact we obtain information about the local stiffness. By using the mechanical model of a vibrating cantilever [1] we are able to derive the indentation modulus of the metallic glass.
To investigate the influence of plastic deformation on the potential energy state of bulk metallic glasses, calorimetry and ultrasonic measurements are performed. Wide-band pulses of a bandwidth of 100 MHz are used to excite the 20 MHz transducer in order to get higher time-resolution. They are used to measure sound velocity as a function of plastic deformation. The results provide evidence of activated relaxations modes.
We would like to thank the SFB 602 for financial support.
[1] M. Kopycinska-Müller, A. Caron, S. Hirsekorn, U. Rabe, H. Natter, R. Hempelmann, R. Birringer and W. Arnold, Phys. Chem. 222, 471, (2008)