USE OF TUNGSTEN COATING ON ITER PLASMA-FACING COMPONENTS

As part of the US ITER research and development activities, approaches to applying tungsten clads to copper, along with the development of a transpiration-cooled tungsten for use as a disruption energy dump, ar e being investigated. Joining is being attempted by diffusion bonding using nickel or titanium interlayers. Reduction in bondline residual s tresses is being accomplished by use of functionally graded layers of tungsten and copper with copper as the continuous phase. Layers are be ing fabricated using vacuum plasma spray, liquid phase sintering and p owder hoc isostatic pressing. Initial metallographic results are promi sing, with fabrication of tensile and high heat flux specimens planned . Direct infiltration of 74% dense tungsten with magnesium and lithium is planned.