Paper number 186


Ch. Englisch1, K. Berroth1, P. Bowen2, H. Hofmann2

1High Performance Ceramics Section, Swiss Federal Laboratories for Materials Testing and Research, Überlandstrasse 129, 8600 Dübendorf, Switzerland
2Powder Technology Laboratory, Swiss Federal Institute of Technology Lausanne
1015 Lausanne, Switzerland

Summary The influence of tin and titanium as alloying elements of copper on the reactions and the wetting behaviour of a copper melt with SiC was investigated using sessile-drop-experiments. Titanium reacts with SiC forming wettable reaction zones and thereby allows the spreading of the melt on the ceramic. Tin as an alloying element leads to a clear reduction of the reactivity with SiC and to an improvement of the wetting behaviour at constant titanium concentrations.
The good wetting behaviour of the tin bronze containing titanium facilitates the pressureless melt infiltration of bronze in titanium activated SiC preforms. The titanium, homogeneously distributed as a metal powder in the preform, dissolves in the melt and reacts with SiC to form wettable TiC interfaces. With a bending strength of 324 MPa and a fracture toughness of 5,9 MPa m1/2 the best mechanical properties were shown by a composite produced by the melt infiltration of a Cu88Sn12-alloy in a preform of composition SiC84Ti16.
Keywords infiltration, wetting, sessile-drop, CuSn, SiC, interfaces, ti-activation, TiC.

Theme : Metal Matrix Composites ; Processing and Forming

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