Dresden 2006 – scientific programme

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MM: Metall- und Materialphysik

MM 20: Amorphous and Liquid Materials I

MM 20.1: Talk

Tuesday, March 28, 2006, 14:45–15:00, IFW D

Soft-Particle-Reinforced Bulk Metallic Glass Composites with High Ductility — •Marco E. Siegrist and Jörg F. Löffler — Laboratory of Metal Physics and Technology, Department of Materials, Swiss Federal Institute of Technology (ETH) Zürich, CH-8903 Zürich, Switzerland

We introduced graphite particles into an amorphous
Zr_52.5Cu_17.9Al₁₀Ni_14.6Ti₅ (Vit 105) matrix with the aim of increasing plasticity and improving the wear and friction properties of monolithic metallic glass. The graphite particle size was varied from 25-75 microns and the reinforcement content from 5-30 vol%. By adjusting the processing parameters part of the graphite can be transformed into ZrC, which allows a systematic change in mechanical properties. This contribution describes the thermophysical and mechanical properties of these graphite/ZrC Bulk Metallic Glass matrix composites. The crystallization sequence of the matrix was studied using differential scanning calorimetry, and the amorphous structure was confirmed by x-ray diffraction. The effect of varying the particle size and carbide content on composite hardness, fracture strength and ductility was investigated. We found that graphite causes a decrease in hardness, whereas carbide formation leads to an increase in hardness compared to the monolithic matrix material. The best mechanical properties were observed with large particles at low volume fractions of graphite, where 18.5% plastic deformation combined with a fracture strength of 1.85 GPa was achieved. The effect of particle reinforcement on fracture behavior was studied using high-resolution scanning electron microscopy.