Development and characterization of tungsten multi-fiber reinforced tungsten composites produced by field assisted sintering technology

In future fusion reactors, tungsten is a main candidate material for the first wall and the divertor. The intrinsic brittleness of tungsten is, however, a concern with respect to the fusion environment. To overcome this drawback, tungsten fiber reinforced tungsten (Wf/W) composites are being developed relying on an extrinsic toughening principle. Recent progress on multi-fiber Wf/W produced by field assisted sintering technology will be presented. Preliminary mechanical tests have been performed in the as-fabricated condition. A pre-notched 3-point bending test (at RT) has been chosen to observe the fracture behavior of the Wf/W. With the optimization of the interface between the fiber and matrix, the possibility to realize the pseudo ductility mechanism has been observed based on the test results. The flexural strength and tensile strength of the Wf/W have been measured by a 4-point bending test and a tensile test, respectively. The Wf/W composites with various fiber volume fractions (from 20% to 60%) have been produced and characterized, both microstructurally and mechanically.