The surface defect distribution in stainless steel irradiated with intensepulsed ion beam (IPIB) of current density above 60A/cm^2 and acceleration voltage 300-500ke V wasdiscussed and analyzed. The defects near the s...The surface defect distribution in stainless steel irradiated with intensepulsed ion beam (IPIB) of current density above 60A/cm^2 and acceleration voltage 300-500ke V wasdiscussed and analyzed. The defects near the surface of stainless steel were generated in two ways:(1) generated by the bombardment of energetic ions and (2) induced by the high level stress near thesurface. Thus the temperature and stress distributions near the steel surface were calculated bymeans of our STEIPIB code, which treated with the thermal-dynamical process in the target irradiatedby the IPIB. Based on these distributions, the generations and movements of these defects werediscussed and compared with the experiment results.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
基金This work is supported by the National Natural Science Foundation of China (Grant No. 19975003 and 10175003).
文摘The surface defect distribution in stainless steel irradiated with intensepulsed ion beam (IPIB) of current density above 60A/cm^2 and acceleration voltage 300-500ke V wasdiscussed and analyzed. The defects near the surface of stainless steel were generated in two ways:(1) generated by the bombardment of energetic ions and (2) induced by the high level stress near thesurface. Thus the temperature and stress distributions near the steel surface were calculated bymeans of our STEIPIB code, which treated with the thermal-dynamical process in the target irradiatedby the IPIB. Based on these distributions, the generations and movements of these defects werediscussed and compared with the experiment results.
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.
