The thermal stability of dispersion-strengthened tungsten as plasma-facing materials: a short review

Abstract

One key challenge for the development of fusion energy is plasma-facing materials. Tungsten-based materials are promising candidates for plasma-facing components (PFCs) in the magnetic confinement nuclear fusion reactors because of their high melt temperature, high-thermal conductivity, high-thermal load resistance, low tritium retention, and low sputtering yield. In fusion reactors, PFCs are exposed to high-thermal flux, because there are some transient events such as plasma disruptions, edge-localized modes, and vertical displacement events (VDEs). Especially, in VDEs, a heat flux of 10-100 MW m −2 with duration of milliseconds-to-several seconds can induce recrystallization and then change the microstructure of tungsten-based plasma-facing materials, leading to instability of microstructures. Then, a significant degradation of material properties is caused such as a reduction of mechanical strength and fracture toughness, a rise in the ductile-to-brittle-transition temperature well, and decrease of irradiation/high-thermal load resistance. Therefore, many efforts were devoted to improve the thermal stability of tungsten-based materials as high as possible, such as oxide dispersion strengthening, carbide dispersion strengthening, and K bubbles dispersion strengthening. Here, the thermal stabilities of various dispersion-strengthened tungsten materials are reviewed by evaluating their recrystallization temperature and the corresponding hardness evolutions. In addition, the possible development trends are proposed.

Recent progress of radiation response in nanostructured tungsten for nuclear application

“…Other vital issues, such as transmutation-induced precipitation [63] and thermal stability [64] of tungsten-based materials under high-dose irradiation, have been studied in micrometer-scale, but relevant research is not abundant to reveal the microscopic and atomic behavior mechanism of irradiated nanocrystalline tungsten.…”

Recrystallization kinetics of larger yttria particle dispersion tungsten alloy warm rolled to 50% thickness reduction

“…In fusion reactors, tungsten-based materials that are strengthened by deformation will experience recovery, recrystallization, and grain growth problems when subjected to long-term high-heat loads [2], resulting in the degradation of mechanical properties, especially recrystallization embrittlement. Embrittlement can pose a hazard to fusion reactors [3], but the use of yttrium oxide dispersion strengthening and deformation strengthening can improve the strength and high-temperature stability of tungsten [4,5]. Currently, there is insufficient research on the recrystallization behavior and microstructure of oxide particle-reinforced rolled tungsten plates under steady-state thermal loads, and further research is needed.…”