Synthesis, characterization and FEM-simulation of W/CuCrZr-composites for extreme thermal applications

Plasma facing components in fusion devices have to withstand extreme thermal loads. To fulfil the desired requirements we investigate tungsten as a plasma facing and CuCrZr as a heat sink material. However, the challenge is the big difference in their coefficients of thermal expansion (CTE). To reduce the thermally induced stresses, we utilize functionally graded materials (W/CuCrZr) as an interlayer between pure W and CuCrZr. In our work the optimized gradient structure will be constructed by means of FEM-simulation of stress-strain curves, CTE- and thermal conductivity values. The simulations are based on photorealistic input from SEM-cross sections of homogeneous W/CuCrZr-composites. The composites (30 to 70 vol.% CuCrZr) were fabricated by pressing of a W-powder/space-holder mixture, debinding/sintering, CuCrZr-infiltration and heat treatment. The measured properties fit quite well with simulated data. Furthermore, the mechanical properties are much better than with pure Cu. First examples of gradient structures will be shown.