316L stainless steel samples, as a widespread used material, were irradiated with HIPIB at the beam parameters of ion energy 300 keV, current density 100, 200 and 300 A/cm2, shot number 10 and pulse duration 75 ns. Th...316L stainless steel samples, as a widespread used material, were irradiated with HIPIB at the beam parameters of ion energy 300 keV, current density 100, 200 and 300 A/cm2, shot number 10 and pulse duration 75 ns. The surface morphology and the phase structure in the near surface region of original and treated samples were analyzed with scanning electron microscopy (SEM) and X-ray diffractometry (XRD). It is shown that the HIPIB irradiation can smooth the surface of the samples, and the preferred orientation is present in the surface layer of irradiated coupons. The influence of HIPIB irradiation on the oxidation behavior of 316L stainless steel at 700℃for up to 100 h was investigated. Electron probe microanalysis (EPMA) was used to study the distribution of elements in the oxidation products. It is found that the oxidation behavior of the irradiated coupons depends greatly on the ion current density of HIPIB. HIPIB irradiation with ion current density of 100 A/cm2 slightly reduces the oxidation rate with respect to the unirradiated coupon. The improvement of the oxidation resistance can be attributed to more oxide of Cr that forms on the surface of the irradiated coupons. In contrast, HIPIB irradiation with ion current density of 200 or 300 A/cm2 is proved to be detrimental, causing a higher oxidation rate.展开更多
Neutral beam injection is one of the effective auxiliary heating methods in magnetic-confinementfusion experiments. In order to acquire the suppressor-grid current signal and avoid the grid being damaged by overheatin...Neutral beam injection is one of the effective auxiliary heating methods in magnetic-confinementfusion experiments. In order to acquire the suppressor-grid current signal and avoid the grid being damaged by overheating, a data acquisition and over-current protection system based on the PXI（PCI e Xtensions for Instrumentation） platform has been developed. The system consists of a current sensor, data acquisition module and over-current protection module. In the data acquisition module,the acquired data of one shot will be transferred in isolation and saved in a data-storage server in a txt file. It can also be recalled using NBWave for future analysis. The over-current protection module contains two modes： remote and local. This gives it the function of setting a threshold voltage remotely and locally, and the forbidden time of over-current protection also can be set by a host PC in remote mode. Experimental results demonstrate that the data acquisition and overcurrent protection system has the advantages of setting forbidden time and isolation transmission.展开更多
This paper studies numerically the thermo-mechanical effects of ZrO2 thermal barrier coatings （TBCs） irradiated by a high-intensity pulsed ion beam in consideration of the surface structure. Taking the deposited ene...This paper studies numerically the thermo-mechanical effects of ZrO2 thermal barrier coatings （TBCs） irradiated by a high-intensity pulsed ion beam in consideration of the surface structure. Taking the deposited energy of ion beams in TBCs as the source term in the thermal conduction equation, the distribution of temperature in TBCs was simulated. Then, based on the distribution, the evolution of thermal stress was calculated by the finite element method. The results show that tensile radial stress formed at the valley of TBC surfaces after irradiation by HIPIB. Therefore, if cracks happen, they must be at valleys instead of peaks. As for the stress waves, no matter whether through peak or valley position, tensile and compressive stresses are present alternately inside TBCs along the depth direction, and the strength of stress decreases with time.展开更多
The structural and phase transformations occurring in the near-surface layers of pre-quenched W6Mo5Cr4V2 high-speed steel (HSS) subjected to intensity pulsed ion beam (IPIB) melting have been investigated. The effect ...The structural and phase transformations occurring in the near-surface layers of pre-quenched W6Mo5Cr4V2 high-speed steel (HSS) subjected to intensity pulsed ion beam (IPIB) melting have been investigated. The effect of IPIB irradiation on wear resistance of the HSS has also been studied. The IPIB consists mainly of Cn+(30%)^0 H+(70%), with a high beam current density of 80A/cm2, acceleration voltage of 250kV, pulse duration of 70 ns. Samples were bombarded with 1, 3, 5 pulses respectively. It has been revealed that after IPIB irradiation the initial martensite in the near-surface layer of HSS changed into austenite and produced residual stresses by using electron microscopy and X-ray diffraction. Redistribution and interlace of dislocations in the irradiated samples were generated under the impact of shock wave. With increasing pulse times gradual liquid-phase dissolution of M6C carbide particles occurs in the near-surface layer and produces nanocrystalline MC. This process results in the decrease of martensite crystal (a-phase) and increase of austenite (y-phase) content and the dispersed carbide. Wear resistance of the HSS is improved by a factor of 2, which is explained by the formation of metastable phases such nanocrystal and residual stresses and the redistribution and interlace of dislocations.展开更多
Interaction between high-intensity pulsed ion beam （HIPIB） and a double-layer target with titanium film on top of aluminum substrate was simulated. The two-dimensional nonlinear thermal conduction equations, with th...Interaction between high-intensity pulsed ion beam （HIPIB） and a double-layer target with titanium film on top of aluminum substrate was simulated. The two-dimensional nonlinear thermal conduction equations, with the deposited energy in the target taken as source term, were derived and solved by finite differential method. As a result, the two-dimensional spatial and temporal evolution profiles of temperature were obtained for a titanium/aluminum double-layer target irradiated by a pulse of HIPIB. The effects of ion beam current density on the phase state of the target materials near the film and substrate interface were analyzed. Both titanium and aluminum were melted near the interface after a shot when the ion beam current density fell in the range of 100 A/cm2 to 200 A/cm2.展开更多
High-current ion beams have become a powerful tool for improving the surface properties of different materials.The prospects of wide commercial use of such beams for material treatment is not only due to the possibili...High-current ion beams have become a powerful tool for improving the surface properties of different materials.The prospects of wide commercial use of such beams for material treatment is not only due to the possibility of improving their properties,but,also for economic expediency.To achieve a high throughput and reduce the cost on ion beam material treatment,ion beams of high average and pulsed power are necessary.This paper gives an overview of work on generation of pulsed and repetitively pulsed beams of accelerated ions with currents ranging from fractions of an ampere to several tens of kA and with pulse duration from several tens of nanoseconds to several hundreds of microseconds.A number of different methods of materials surface properties modification using high power and intense ion beam and plasma are considered.展开更多
基金Project (2003AA305610) supported by the Hi-tech Research and Development Program of China
文摘316L stainless steel samples, as a widespread used material, were irradiated with HIPIB at the beam parameters of ion energy 300 keV, current density 100, 200 and 300 A/cm2, shot number 10 and pulse duration 75 ns. The surface morphology and the phase structure in the near surface region of original and treated samples were analyzed with scanning electron microscopy (SEM) and X-ray diffractometry (XRD). It is shown that the HIPIB irradiation can smooth the surface of the samples, and the preferred orientation is present in the surface layer of irradiated coupons. The influence of HIPIB irradiation on the oxidation behavior of 316L stainless steel at 700℃for up to 100 h was investigated. Electron probe microanalysis (EPMA) was used to study the distribution of elements in the oxidation products. It is found that the oxidation behavior of the irradiated coupons depends greatly on the ion current density of HIPIB. HIPIB irradiation with ion current density of 100 A/cm2 slightly reduces the oxidation rate with respect to the unirradiated coupon. The improvement of the oxidation resistance can be attributed to more oxide of Cr that forms on the surface of the irradiated coupons. In contrast, HIPIB irradiation with ion current density of 200 or 300 A/cm2 is proved to be detrimental, causing a higher oxidation rate.
基金supported by National Natural Science Foundation of China(No.11575240)Key Program of Research and Development of Hefei Science Center,CAS(grant 2016HSC-KPRD002)
文摘Neutral beam injection is one of the effective auxiliary heating methods in magnetic-confinementfusion experiments. In order to acquire the suppressor-grid current signal and avoid the grid being damaged by overheating, a data acquisition and over-current protection system based on the PXI（PCI e Xtensions for Instrumentation） platform has been developed. The system consists of a current sensor, data acquisition module and over-current protection module. In the data acquisition module,the acquired data of one shot will be transferred in isolation and saved in a data-storage server in a txt file. It can also be recalled using NBWave for future analysis. The over-current protection module contains two modes： remote and local. This gives it the function of setting a threshold voltage remotely and locally, and the forbidden time of over-current protection also can be set by a host PC in remote mode. Experimental results demonstrate that the data acquisition and overcurrent protection system has the advantages of setting forbidden time and isolation transmission.
基金Project supported by the National Natural Science Foundation of China (Grant No 50575037)the Doctoral Foundation of Dalian University of China (Grant No SBQ200810)
文摘This paper studies numerically the thermo-mechanical effects of ZrO2 thermal barrier coatings （TBCs） irradiated by a high-intensity pulsed ion beam in consideration of the surface structure. Taking the deposited energy of ion beams in TBCs as the source term in the thermal conduction equation, the distribution of temperature in TBCs was simulated. Then, based on the distribution, the evolution of thermal stress was calculated by the finite element method. The results show that tensile radial stress formed at the valley of TBC surfaces after irradiation by HIPIB. Therefore, if cracks happen, they must be at valleys instead of peaks. As for the stress waves, no matter whether through peak or valley position, tensile and compressive stresses are present alternately inside TBCs along the depth direction, and the strength of stress decreases with time.
文摘The structural and phase transformations occurring in the near-surface layers of pre-quenched W6Mo5Cr4V2 high-speed steel (HSS) subjected to intensity pulsed ion beam (IPIB) melting have been investigated. The effect of IPIB irradiation on wear resistance of the HSS has also been studied. The IPIB consists mainly of Cn+(30%)^0 H+(70%), with a high beam current density of 80A/cm2, acceleration voltage of 250kV, pulse duration of 70 ns. Samples were bombarded with 1, 3, 5 pulses respectively. It has been revealed that after IPIB irradiation the initial martensite in the near-surface layer of HSS changed into austenite and produced residual stresses by using electron microscopy and X-ray diffraction. Redistribution and interlace of dislocations in the irradiated samples were generated under the impact of shock wave. With increasing pulse times gradual liquid-phase dissolution of M6C carbide particles occurs in the near-surface layer and produces nanocrystalline MC. This process results in the decrease of martensite crystal (a-phase) and increase of austenite (y-phase) content and the dispersed carbide. Wear resistance of the HSS is improved by a factor of 2, which is explained by the formation of metastable phases such nanocrystal and residual stresses and the redistribution and interlace of dislocations.
基金supported by National Natural Science Foundation of China (No.10975026)
文摘Interaction between high-intensity pulsed ion beam （HIPIB） and a double-layer target with titanium film on top of aluminum substrate was simulated. The two-dimensional nonlinear thermal conduction equations, with the deposited energy in the target taken as source term, were derived and solved by finite differential method. As a result, the two-dimensional spatial and temporal evolution profiles of temperature were obtained for a titanium/aluminum double-layer target irradiated by a pulse of HIPIB. The effects of ion beam current density on the phase state of the target materials near the film and substrate interface were analyzed. Both titanium and aluminum were melted near the interface after a shot when the ion beam current density fell in the range of 100 A/cm2 to 200 A/cm2.
基金support of the Russian Foundation of Fundamental Investigations(grant No.10-08-00828-a)
文摘High-current ion beams have become a powerful tool for improving the surface properties of different materials.The prospects of wide commercial use of such beams for material treatment is not only due to the possibility of improving their properties,but,also for economic expediency.To achieve a high throughput and reduce the cost on ion beam material treatment,ion beams of high average and pulsed power are necessary.This paper gives an overview of work on generation of pulsed and repetitively pulsed beams of accelerated ions with currents ranging from fractions of an ampere to several tens of kA and with pulse duration from several tens of nanoseconds to several hundreds of microseconds.A number of different methods of materials surface properties modification using high power and intense ion beam and plasma are considered.
