Tungsten(W)is a promising candidate material for the plasma-facing components in future fusion reactors.However,it has issues regarding the intrinsic brittleness as well as operational embrittlement.Tungsten fiber rei...Tungsten(W)is a promising candidate material for the plasma-facing components in future fusion reactors.However,it has issues regarding the intrinsic brittleness as well as operational embrittlement.Tungsten fiber reinforced tungsten(W_(f)/W)composites overcome these issues by using extrinsic toughening mechanisms.Due to neutron irradiation and high-temperature recrystallization during fusion operation,the ductility of the fibers may degrade over a long period of service.Therefore,it is necessary to investigate the fracture behavior of W_(f)/W composites with brittle fibers.In the present work,the tungsten fibers were embrittled by carbonization.Subsequently,the continuous brittle W_(f)/W composite with yttrium oxide(Y_(2)O_(3))interface was fabricated by the field-assisted sintering technology process.The microstructure of the prepared W_(f)/W composites was characterized.The fracture behavior and toughening mechanisms were discussed in detail based on the experimental results of 3-point bending tests and the corresponding finite element simulation.The composites show a pseudo-ductile fracture behavior.Cracks are hindered and deflected by the de-bonded fiber-matrix interface.The extrinsic toughening mechanisms of interface de-bonding,crack bridging,and fiber pull-out are active.This indicates the reinforcement concept still works even though all components in the W_(f)/W are brittle.展开更多
基金funded by the European Union via the Euratom Research and Training Programme(Grant Agreement No 101052200-EUROfusion)financially supported by the China Scholarship Council(CSC)(No.202007000034)。
文摘Tungsten(W)is a promising candidate material for the plasma-facing components in future fusion reactors.However,it has issues regarding the intrinsic brittleness as well as operational embrittlement.Tungsten fiber reinforced tungsten(W_(f)/W)composites overcome these issues by using extrinsic toughening mechanisms.Due to neutron irradiation and high-temperature recrystallization during fusion operation,the ductility of the fibers may degrade over a long period of service.Therefore,it is necessary to investigate the fracture behavior of W_(f)/W composites with brittle fibers.In the present work,the tungsten fibers were embrittled by carbonization.Subsequently,the continuous brittle W_(f)/W composite with yttrium oxide(Y_(2)O_(3))interface was fabricated by the field-assisted sintering technology process.The microstructure of the prepared W_(f)/W composites was characterized.The fracture behavior and toughening mechanisms were discussed in detail based on the experimental results of 3-point bending tests and the corresponding finite element simulation.The composites show a pseudo-ductile fracture behavior.Cracks are hindered and deflected by the de-bonded fiber-matrix interface.The extrinsic toughening mechanisms of interface de-bonding,crack bridging,and fiber pull-out are active.This indicates the reinforcement concept still works even though all components in the W_(f)/W are brittle.
