Troisiéme Conférence Européenne sur les Matériaux et les Procédés Avancés
J. Phys. IV France 03 (1993) C7-1043-C7-1052
Ceramic to metal direct brazingF. MORET1 and N. EUSTATHOPOULOS2
1 CEREM/Laboratoire de Génie des Matériaux, CENG, 85X, 38041 Grenoble cedex, France
2 INPG/LTPCM, ENSEEG, BP. 75, 38402 Saint Martin d'Hères, France
The production of important components like first walls of thermonuclear power reactors, advanced automotive or aeronautic turbines and heat exchangers depends on the control of ceramic to metal joining techniques, especially direct brazing. Recent advances in two fundamental aspects of such techniques are reviewed: thermodynamics and mechanics. About thermodynamics, a general theory of wetting and adhesion of active filler alloys on oxide ceramics is described. This approach allows the determination of optimal braze compositions. Some of the concepts of this approach are used for non oxide ceramics. Due to a complex stress field existing in the ceramic at the location of crack initiation and propagation, accurate failure prediction of ceramic to metal assemblies remains a challenge. Nevertheless, simple analytical calculations are ofen a useful tool. For more advanced analysis, determination ofjoint constitutive laws by inverse method and careful finite element enmeshment in the viciniv of the joint allow accurate stress field calculations.
© EDP Sciences 1993