Sputtering and redeposition behavior of VBe12 compound and of Ti--Cu--Li composites within a fusion tokamak environment

VBe12 compound and porous titanium composites infiltrated with a lithium bearing copper alloy have been investigated as a means of reducing fusion plasma impurities and sputter erosion associated with fusion tokamak limiter and divertor surfaces. These materials possess high-temperature strength and melt-layer stability properties in conjunction with the self-sustainment of a low-Z overlayer that inhibits erosion of the underlying structural substrate. The sputter erosion and redeposition properties of these materials have been analyzed by calculating the sputtering coefficients via TRIM, which are subsequently used in the REDEP code to evaluate their performance for various plasma-edge temperature regimes. The results have been compared to elemental beryllium, tungsten, and graphite on the basis of minimizing plasma impurities and material erosion, suppressing runaway self-sputtering, and/or enhancing thermal properties