Net Shape Gradient W-Cu Plasma Facing Components by Pressure Infiltration

192 Net Shape Gradient W-Cu Plasma Facing Components by Pressure Infiltration--Foster-Miller, Inc., 350 Second Avenue, Waltham, MA 02154-1104; (617) 684-4239 Dr. Prashant Karandikar, Principal Investigator Mr. Adi R. Guzdar, Business Official DOE Grant No. DE-FG02-97ER82378 Amount: $74,975 Tungsten, a leading candidate for material to be used as a heat shield in the magnetic fusion energy experiment International Thermonuclear Experimental Reactor (ITER), must be reliably attached to a cooling structure consisting of a copper alloy. The methods for attaching tungsten to the cooling structure, mechanical joining, brazing and hot isostatic pressing have several limitations such as differential thermal expansion-induced residual stresses, high cost, activation and transmutation due to radiation and related disposal problems, and multiple processing steps. This project will overcome the limitations of current technologies by fabricating tungsten-copper plasma facing components by pressure infiltration in a single step. The component will have a tungsten armor tile on one side and an oxide dispersion strengthened copper alloy heat sink on the other. A very gradual tungsten-copper composition gradient will be obtained in the transition region in the middle so as to mitigate thermal shock related stresses. In Phase I, the gradient will be designed and several prototype components will be fabricated. Mechanical property, thermal conductivity, and high heat flux measurements will be made and compared with baseline components. In Phase II, detailed gradient design will be made, selected design will be fabricated and tested. The optimum component design will be used to fabricate actual components for testing in the fusion reactor environment. Commercial Applications And Other Benefits as described by the awardee: Some of the potential applications of this approach include: joining of refractory metals to high thermal conductivity composites for medical and industrial X-Ray tube targets; gas tungsten arc welding (GTAW) electrodes and biomedical X-Ray anodes.