Dresden 2006 – wissenschaftliches Programm

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MM: Metall- und Materialphysik

MM 2: Symposium Severe Plastic Deformation I

MM 2.4: Vortrag

Montag, 27. März 2006, 12:15–12:30, IFW A

Synthesis of nanostructured Al-Y-Fe using SPD processing — •Nancy Boucharat¹, Rainer Hebert^1,2, Harald Rösner¹, and Gerhard Wilde¹ — ¹Forschungszentrum Karlsruhe, Institute of Nanotechnology, P.O.B. 3640, 76021 Karlsruhe, Germany — ²University of Wisconsin-Madison, Department of Materials Science and Engineering, Madison, WI 53706, USA

A common way to produce nanostructures from Al-rich glass-forming alloys is to apply low temperature isothermal treatments. However, plastic deformation can also induce crystallization in metallic glasses. Thus, deformation at large strains might present an alternative route for producing bulk nanostructures of adjustable grain size. We report here structural analyses of an Al-Y-Fe glass that has been subjected to high-pressure torsion straining at room temperature. The results show a remarkably high number density of Al-nanocrystals compared to the values obtained after annealing at low temperatures or after cold rolling at moderate strains, respectively. The nanocrystals appear to be distributed homogeneously throughout the sample without any evidence of strong coarsening. Moreover, the comparison between deformation-mediated nanocrystallization by applying either high pressure torsion straining or cold rolling is discussed with respect to the likely mechanisms underlying the nanocrystallization during deformation. These results form the basis for the development of advanced processing strategies for producing new nanostructures with high nanocrystal number densities giving rise to increased stability and improved performance of the nanoscale microstructure. Support by the DFG is gratefully acknowledged.