Interface and mechanical properties of the single-layer long fiber reinforced Wf/W composites fabricated via field assisted sintering technology

Tungsten fiber reinforced tungsten composites (Wf/W) show a pseudo-ductile behavior because of extrinsic toughening mechanisms such as interface de-bonding, pull-out and plastic deformation of the fiber. In the present work, single-layer long fiber Wf/W composites with and without yttrium oxide (Y2O3) interface were fabricated by a field assisted sintering technology (FAST) process. The microstructure and mechanical properties of the prepared Wf/W composites were characterized. The fracture behavior and toughening mechanisms were analyzed in detail combining the results of experiments and finite element modelling. Wf/W composites with Y2O3 interface (weak interfacial strength) show a typical pseudo-ductile fracture behavior and a higher flexural strength than the composites without Y2O3 interface (strong interfacial strength). The fracture energy dissipation is mainly driven by plastic deformation of the fibers, but interface de-bonding is a necessary factor to ensure any extrinsic toughening mechanisms.