Ceramic to metal direct brazing
Résumé
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.
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Articles anciens
Origine : Accord explicite pour ce dépôt
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