Regensburg 2004 – wissenschaftliches Programm

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M: Metallphysik

M 9: Flüssige und amorphe Metalle III

M 9.4: Vortrag

Montag, 8. März 2004, 17:15–17:30, H16

Zr-Nb-Cu-Ni-Al glass or nanocrystalline matrix composites containing dendritic bcc phase precipitates — •Uta Kuehn, Juergen Eckert, Nicolle Radtke, Norbert Mattern, and Ludwig Schultz — IFW Dresden, P.O. Box 270016, D-01171 Dresden

This work presents results on the microstructure and the resulting mechanical properties of the Zr66Nb13Cu8Ni6.8Al6.2 multicomponent alloy with a glassy or a nanocrystalline matrix and ductile bcc precipitates. This composite material was prepared by arc-melting, copper mold casting and melt spinning with different sample dimensions and, therefore, different cooling rates and microstructures. The structure of the samples was investigated by XRD, OM, SEM, TEM and DSC. Room temperature compression tests were realized with an electromechanical testing device under quasistatic loading. The bulk samples exhibit significantly improved mechanical behaviour compared to monolithic glass, since the in-situ formed nanocrystalline matrix composites undergo work hardening and plastic deformation prior to failure, whereas monolithic glass forms highly localized shear bands, which consequently leads to catastrophic failure. High ultimate compression stress combined with high plastic strain is mainly dominated by a well-balanced ratio of the extant phases. Surprisingly also a nanocrystalline matrix leads to high elastic strain values. Illustrated by the composition presented in this study and different cooling rates we show the possibility of obtaining tailored mechanical properties for such composite materials.