Study Of Irradiation Damage By High-intensity Pulsed Ion Beam And He Ions Beam On The Fe₈₀B₁₃Si₇ Alloy With Different Structure

Metallic glass has the structure with long range disordered and short range ordered.Compared with the traditional crystal materials,metallic glass has better irradiation resistance due to its disordered structure,absence of defects such as grain boundary and dislocation.Fe-based metallic glass has the characteristics of no neutron activation elements,high crystallization temperature and high strength,which is expected to be a candidate material for irradiation resistant in fusion devices.However,the thermal instability of Fe-based metallic glass restricts its specific application.In the irradiation environment of fusion device,in addition to neutron irradiation up to 14 MeV and plasma irradiation?He ions?,there is also strong thermal radiation.For this reason,Fe₈₀B₁₃Si₇ alloys are selected as the research object in this paper.The research includes two parts:For the first one,the thermal stability of Fe₈₀B₁₃Si₇ metallic glass and crystal alloy with the same composition are studied.The second is to study the effects of the joint irradiation of thermal irradiation and He ions on Fe₈₀B₁₃Si₇metallic glass.HIPIB's unique thermal and thermoelastic wave effects are very suitable for simulating thermal radiation in fusion devices,and can even simulate instantaneous thermal shock when the plasma is broken and unstable.In this paper,HIPIB irradiation is used to study the thermal stability of Fe₈₀B₁₃Si₇ metallic glass and crystal alloy.At the same time,HIPIB and He ion joint irradiation is be used to simulate the irradiation damage of Fe₈₀B₁₃Si₇ metallic glass caused by He ion irradiation in a strong thermal environment.In this paper,the experiment of HIPIB irradiation was performed on the TEMP-4M high-intensity pulsed ion beam device at Tomsk Polytechnic University in Russia.The acceleration voltage is 200-240 kV,the pulse width is 90 ns,and the pulse interval is 10 s.The ion beam consists of 85%Cⁿ⁺?mostly C⁺?and 15%H⁺.The experimental parameters of HIPIB irradiation were divided into three groups.The energy density and pulse times of ion beam were 60 A/cm²,50 times;20-30 A/cm²,100 times;10-20 A/cm²,300 times respectively.The He ion beam irradiation experiment was completed at the 320kV-ECR experimental terminal of the institute of modern physics of the Chinese academy of sciences in Lanzhou,with the ion beam energy of 300 keV.The joint irradiation parameters of HIPIB and He ion beam were:The HIPIB energy density was 60 A/cm²,and the number of pulses was 3;The irradiation doses of He ion beam were 2.0×10¹77 ions/cm²,4.0×10¹77 ions/cm² and 6.0×10¹77 ions/cm² respectively.In the HIPIB irradiation,TEM analysis of the cross-section showed that after HIPIB irradiation,the atoms in amorphous were aggregated and migrated,and the arrangement of atoms became uneven,no nanocrystal was observed.For the crystal,Fe₃B,Fe₃Si,Fe₂B and Fe₃C nanocrystals appeared except for the main structure of the?-Fe phase after HIPIB irradiation.A mass of defects appeared in the crystal.Meanwhile,XRD results showed that the lattice parameters of?-Fe phase were decreased.The effect range of the structure and defects of the crystal and the arrangement of amorphous atoms by irradiation were far beyond the incident ion range.After HIPIB irradiation,the surface of amorphous showed no obvious irradiation damage,and the surface of crystal showed wavy undulations.The roughness of both two alloys were increased,and the surface diffusion caused by the thermal driving and ion-induced was the main mechanism of surface evolution.The decrease of the surface reflectivity of the amorphous was smaller than that of the crystal.In the HIPIB and He ion joint irradiation,the amorphous alloy still retained its original amorphous structure and had no obvious irradiation damage on the surface when the He ion dose reached 6×10¹⁷ ions/cm².Compared with single HIPIB irradiation,the surface evolution mechanism of the HIPIB+He ion joint irradiation changed from volume diffusion to viscous flow or surface diffusion.The roughness of two were slightly larger than the original unirradiated alloy.HIPIB irradiation and joint irradiation introduced vacancy-like defects into Fe₈₀B₁₃Si₇ amorphous alloy,and more vacancy-like defects were introduced by joint irradiation.Under the two irradiation modes,no obvious irradiation damage was found on the surface of Fe₈₀B₁₃Si₇ amorphous alloy,and the amorphous structure was still in good condition.Fe-based metallic glass has good irradiation resistance and irradiation stability,which provides reference for the selection of irradiation resistant materials in fusion devices.