Joining of Tungsten Armor Using Functional Gradients

40903 November 18, 1996 Plasma Processes, Inc. Due to its high melting point, good thermal conductivity, low sputtering rate, and disruption resistance, tungsten armor is being considered for magnetic fusion energy devices such as the International Thermonuclear Experimental Reactor (ITER). However, the joining of tungsten tiles (3-5 mm thick) to copper substrates remains a critical issue. Most contemporary joining techniques (welding, fastening, etc.) can not be used. Brazing and diffusion bonding may make joints possible, but these technologies are difficult to use on large curved reactor surfaces. This project will use innovative functional gradient technologies to strongly join tungsten to copper alloy heat sinks without the use of silver or gold. The copper/tungsten functional gradient maximizes the integral bonding of the dissimilar metals while minimizing thermal strains that would otherwise develop. Divertor mockups will be made and thermal cycled at ITER heat fluxes to prove the superior thermal fatigue life of the innovative functional gradient joint. Anticipated Results/Potential Commercial Applications as described by the awardee: Commercial applications include furnace crucibles, rocket engine combustion chambers, high temperature containment assemblies for hazardous materials, welding electrodes, MHD generator electrodes, etc.