A comparison of the structure and mechanical properties of commercially pure tungsten rolled plates for the target of the European spallation source

Six suppliers from several countries were asked to furnish parallelepiped 10 × 30 × 80 mm3 samples of commercial purity tungsten machined from rolled plates in view of selecting a provider of tungsten bricks for the target of the European neutron spallation source, ESS, under construction in Lund (Sweden). Sample surfaces were to be ground and free from visible defects or oxidation. The material should be rolled after sintering. A minimum room temperature tensile strength of 600 MPa was specified. The samples were submitted to different blind mechanical tests, measurement of physical properties and structural observations in order to assess their suitability for the application. We present here a summary of their main measured properties. The dispersion of results is noteworthy; the exercise allowed to sort-out technically eligible candidates for the application.