Study On Recrystallization Behavior Of Rolled Yttrium Oxide Dispersion Strengthen Tungsten

Tungsten-based materials are considered to be the most promising plasma-facing materials(PFM)due to their excellent high-temperature properties.Tungsten-based material is required to withstand extremely high heat flux(10?20 mW·s^-1),high energy neutron irradiation(14 Me V)and high plasma flux(1×10²⁰?1×10²⁴ m^-1·s^-1)in nuclear fusion environment.The long-term high-temperature service environment will inevitably cause recovery,recrystallization and grain coarsening in the deformed tungsten-based material.The intergranular bond strength of polycrystalline tungsten is weak,the recrystallization process will change the internal stress at the grain boundary and the impurities will be enriched around the high-angle grain boundaries.The grain coarsening will further aggravate the expansion of the brittle crack extension zone leading to recrystallization embrittlement and the lose of the mechanical properties.The isothermal annealing experiment and the hardness test indicated that the doped yttrium oxide particles increased the mechanical properties and recrystallization temperature of tungsten.The hardness degradation curve obtained after isothermal annealing proves that WY50 undergoes three typical stages including recovery,recrystallization and grain growth throughout the annealing process.The Johnson-Mehl-Avrami-Kolmogorov(JMAK)model corrected with the introduction of the incubation time t_inc well characterizes the hardness degradation and recrystallization volume fraction over time in the recrystallization process.The hardness change process in the recovery phase can be accurately fitted by the Kuhlmann model.At the same time,the activation energy of WY50 was calculated to be 508(1±4%)k J/mol by Arrhenius equation.The EBSD was used to deep analyze the changes rulers of microstructure and texture of sintered,rolled plate and samples at different stages of the recrystallization process.The results show that the microstructure of the sintered compact consists of equiaxed crystals with different sizes,almost no texture is found and the orientation difference approaches the Mackenzie distribution.After plastic deformation,a typical deformed structure is formed and the texture is obviously enhanced.As the recrystallization progresses,the initial rolled deformed structure is replaced by recrystallized grains,eventually forming a large number of undistorted fine recrystallized grains.The orientation difference is restored to the Mackenzie distribution.The sum of the recovery area and the recrystallized area calculated from the EBSD results is approximately equal to the recrystallization volume fraction calculated by the hardness value.Texture analysis shows that the rolling deformation makes WY50 form a strong?texture({112}<110>component)and?texture(stronger{111}<110>component and weaker{111}<112>Component).However,the texture changes caused by the recrystallization process at different annealing temperatures are not the same.