Paper number 739

CHEMICAL COMPATIBILITY BETWEEN ALUMINIUM BASE MATRICES AND LIGHT REFRACTORY CARBIDE REINFORCEMENTS

J.C. Viala, M. Peronnet, F. Bosselet and J. Bouix

Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Université Lyon 1, F 69622 Villeurbanne Cedex, France

Summary

The main features of the interface chemistry of Al/B4C, Al/TiC and Al/SiC couples at temperatures up to 1000°C are presented and discussed in terms of thermodynamics, kinetics and reaction mechanism. The Al/B4C couple appears reactive whatever the temperature whereas a reactive-non reactive transition occurs at 812°C on heating for the Al/TiC couple and at 650°C on cooling for the Al/SiC couple. The reaction products are Al3BC and AlB2 or -AlB12 for the Al/B4C couple, Al4C3 and Al3Ti for Al/TiC and finally Al4C3 and dissolved silicon for Al/SiC. Whatever the couple, interaction always proceeds via a dissolution-precipitation mechanism which ends in certain instances with the passivation of the base carbide surface by a continuous Al3BC or Al4C3 layer. Some examples are given illustrating how advantage can be taken of these features for interface tailoring.

Keywords

metal matrix, aluminium, boron carbide, titanium carbide, silicon carbide, interface, chemical reactions.