Assessment of mechanical properties of SPS-produced tungsten including effect of neutron irradiation

Production and supply of tungsten for the first wall fusion application is becoming an important aspect given the progress of ITER construction. Exploration of advanced routes alternative to the conventional powder metallurgy is currently undertaken. In this work we have assessed a potential of the spark plasma sintering (SPS) production route to deliver well controlled microstructure, chemistry and mechanical properties of bulk tungsten as a first step. SPS-produced tungsten was sintered at 2000 degrees C and was characterized in terms of mechanical properties, namely: tensile, three point bending and fracture toughness data in the temperaure range of 250-600 degrees C. Then, neutron irradiation was performed at 600 degrees C and the change of the fracture toughness was measured after irradiation together with the characterization of the fracture surface. The results are compared with those obtained for the commerically produced swaged tungsten irradiated and tested in equivalent conditions. The obtained results show that SPS technology offers the production of bulk tungsten with a good potential for further optimization (by e.g. swaging/rolling). Neutron irradiation causes the reduction of the fracture toughness comparable to the one induced in the commercially produced tungsten.