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M: Metallphysik

M 14: Postersitzung

M 14.9: Poster

Thursday, March 30, 2000, 15:00–19:00, C

Mechanically Alloyed Zr-based Metallic Glass Composites with Embedded Nanocrystalline Particles — •S. Deledda, J. Eckert und L. Schultz — IFW Dresden, Institut für Metallische Werkstoffe, Postfach 27 00 16, 01171 Dresden

We report on the synthesis of metallic glass composites containing ceramic particles as second phase. Pure elemental powders with nominal composition Zr₅₅Cu₃₀Al₁₀Ni₅ were mechanically alloyed together with different volume fractions of CaO or ZrC particles to produce a mixture in which the oxide or carbide particles are reduced to nanometer size and are homogeneously dispersed in the amorphous matrix. X-ray diffraction and calorimetric measurements were carried out for different volume fraction of ceramic phase. Whereas glassy phase with distinct supercooled liquid region is maintained up to about 5 vol.% of nanoscale CaO particles, no clear evidence for a glass transition is found for large volume fractions. This will be discussed with respect to partial dissolution of particles upon milling. Furthermore, the kinetics of crystallization upon constant-rate heating and isothermal annealing of the composites are investigated.