Characterization of brazed joints of C-C composite to Cu-clad-Molybdenum

Carbon-carbon composites with either CVI matrix or resin-derived matrix were joined to copper-clad-molybdenum using two active braze alloys, Cusil-ABA (1.75% Ti) and Ticusil (4.5% Ti). The brazed joints revealed good interfacial bonding, preferential precipitation of Ti at the composite/braze interface, and a tendency toward de-lamination in resin-derived C-C composite due to its low inter-laminar shear strength. Extensive braze penetration of the inter-fiber channels in the CVI C-C composites was observed. The relatively low brazing temperatures (<950 degrees C) precluded melting of the clad layer and restricted the redistribution of alloying elements but led to metallurgically sound composite joints. The Knoop microhardness (HK) distribution across the joint interfaces revealed sharp gradients at the Cu-clad-Mo/braze interface and higher hardness in Ticusil (similar to 85-250 HK) than in Cusil-ABA (similar to 50-150 HK). These C-C/Cu-clad-Mo joints with relatively low thermal resistance may be promising for thermal management applications. (C) 2008 Elsevier Ltd. All rights reserved.