Hamburg 2001 – scientific programme

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M: Metallphysik

M 22: Symposium Unterkühlte Metallschmelzen VIII

M 22.6: Fachvortrag

Tuesday, March 27, 2001, 16:30–16:45, S12

Thermal stability of mechanically alloyed Zr-Cu-Al-Ni glass composites containing ceramic particles as a second phase — •S. Deledda, J. Eckert und L. Schultz — IFW Dresden, Insitut für Metallische Werkstoffe, Postfach 27 00 16, 01171 Dresden

Metallic glass matrix composites were produced by mechanically alloying pure elemental powders with nominal composition Zr₅₅Cu₃₀Al₁₀Ni₅ together with up to 30 vol.% of ZrC and 20 vol.% of CaO particles. Calorimetric investigations shows that when calcium oxide is the second phase, a supercooled liquid region is maintained only for volume fractions lower than 15%. On the other hand, the glass forming ability of the system is not affected by the presence of the carbide particles. Changes in the thermal stability, i.e. the glass transition temperature T_g and the crystallization temperature T_x, were observed in all cases and suggest the occurrence of a partial dissolution of the ceramic phase which eventually results in deviations in the overall composition of the matrix. This is supported by the comparison with thermal stability data for the same system alloy containing small carbon or calcium additions.