Characterization of brazed joints of C-C composite to Cu-clad-Molybdenum
Abstract 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 ( C/Cu-clad-Mo joints with relatively low thermal resistance may be promising for thermal management applications.
High performance heat sink for surface mount applications
Surface-mounted electronic module configurations are sensitive to thermal cycling because the reduced compliance between the component and module increases the thermally induced strain in the solder joint. Providing a thermal match between the component and the module reduces this strain, reduces low-cycle fatigue damage, and increases solder joint life. One way of achieving this thermal match is through the use of a thermally matched heat sink. In addition to having the required coefficient of thermal expansion (CTE), heat sinks for surface-mount avionic configurations require low weight and high thermal conductivity. A heat sink has been developed that has thermal conductivity close to aluminum, a CTE close to ceramic, and a weight density only 8% higher than aluminum. The flexural modulus of this heat sink is 40% higher than aluminum, which results in improved vibration performance. It is laminated, consisting of a thicker layer of graphite between thinner layers of copper-clad molybdenum,.<<ETX>>
Thermodynamics on the Carbochlorination of Titanium-bearing Ores
The equilibrium compositions of the multi-component, multi-phase and multi-reaction system of carbochlorination of titanium-bearing ores are calculated with HSC, a computational chemistry software. The thermodynamic equilibrium calculation of the reaction system shows that a complete conversion of titanium-bearing ores is feasible at a temperature near 200oC. At temperatures ranging from 800 to 1600oC, the products of the reaction system are all in gaseous phase. Thermodynamic analysis accords with the industrial practice. The simulated results provide reasonable scientific basis for improving suitable technological conditions of the carbochlorination reduction.