Dresden 2011 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 31: Postersitzung II
MM 31.47: Poster
Mittwoch, 16. März 2011, 17:15–18:45, P5
Determination of the pressure activation volume via the deformation of nanocrystalline PdAu-samples with different shear-compression-ratios — •Christian Braun and Rainer Birringer — Universität des Saarlandes, FR 7.2 Experimentalphysik, Campus D2.2, 66123 Saarbrücken
The recently introduced miniaturisation of the shear-compression-specimen [1] allows the mechanical testing of small samples such as inert gas condensed nanocrystalline materials via a dominant shear-deformation. The stress-strain-curve and further parameters as strain components or hydrostatic pressure P are calculated by FEM-simulations based on the experimental force-displacement-diagram. By means of a variation of the shear-angle, it is possible to vary the shear-compression-ratio and the hydrostatic pressure P in the deformation zone. This permits the determination of the differential quotient ∂ σ / ∂ P which is necessary to calculate the pressure activation volume Δ vP given as Δ vP = ∂σ/∂ PΔ vσ, where Δ vσ is the shear activation volume obtained from stress-strain-curves taken at different strain rates [2]. On this poster we present first simulation results for the expected variation of P for different shear angles as well as first experimental findings measured at nanocrystalline Pd90 Au10-samples with an average grain diameter of about 10 nm.
[1] M. Ames, J. Markmann, R. Birringer, Mater. Sci. Eng. A 528, 526 (2010), [2] A.S. Argon, Strengthening Mechanisms in Crystal Plasticity, OUP (2007)