Study On Recrystallization Behavior Of Yttrium Oxide Particle-reinforced Rolled Tungsten Plates And The Effect On Irradiation Damage

Tungsten-based materials have the advantages of high melting point,high thermal conductivity and low sputtering rate,and are considered to be the most potential plasma-oriented materials in nuclear fusion materials.During service,tungsten-based materials will be subjected to multiple coupling effects,such as extreme thermal load(10-20 m W/m²),high-flux ion(10²⁰-10²⁴ ions/(m²·s))and high-energy neutron irradiation(14 Me V).The static recrystallization of tungsten-based materials will occur under high thermal load conditions for a long time,which will lead to changes in mechanical properties,thermal load resistance and radiation resistance.The change of these properties will directly affect the service life of the materials,and also affect the safety of the fusion device.At present,the research on the recrystallization behavior of tungsten-based materials under steady state thermal load and its resistance to ion irradiation is not enough.In this paper,the recrystallization behavior of 67%yttrium oxide dispersion reinforced tungsten(WY67)was simulated by isothermal annealing experiments at different temperatures.The process of He plasma irradiation on WY67 materials with different volume fraction of recrystallization in fusion reactor was simulated by using linear plasma experimental equipment.The properties and microstructure changes of WY67 materials under the indirect synergistic effects of high temperature thermal loading and ion irradiation were investigated.In the isothermal annealing experiment,WY67 was annealed at relatively low temperatures of 1300°C and 1350°C for a long time.The microstructure of WY67was mainly recovered,and there was no obvious change compared with that of the rolled microstructure.At relatively high annealing temperatures of 1375°C,1400°C and 1450°C,the initial deformed microstructure is gradually replaced by recrystallized grains with the increase of annealing time,and complete recrystallization occurs after annealing for 72 h,36 h and 3 h,respectively.The recovery and recrystallization behavior of WY67 during annealing was described by Kuhlmann model and modified JMAK model respectively.The recrystallization activation energy of WY67 was 1089(1±5%)k J/mol by fitting the Arrhenius relation.The recrystallization temperature of WY67 is about 1400°C.In the experiments of He ion irradiation,when the irradiation temperature is 573 K,the surface microstructure of the samples with different volume fraction of recrystallization is produced at the nano-scale.The radiation damage degree of the material surface increases with the increase of radiation fluence.Compared with the rolled samples,the recrystallized samples produced more dense and more nano-scale structures after irradiation at low irradiation fluence.At high irradiation fluence,nano-scale pores appear on the surface of the recrystallized samples.The surface damage morphology of the partially and fully recrystallized samples is similar.When the irradiation temperature was 1073 K,Fuzz structures were generated on the surface of the samples with different recrystallization volume fraction,and Fuzz structures gradually gathered on the surface of the samples with the increase of the recrystallization volume fraction.The surface roughness analysis shows that under the same irradiation condition,the surface roughness increases with the increase of the recrystallization volume fraction.In addition,yttrium oxide particles in tungsten matrix are more easily etched during the irradiation process.