Applied Fundamental Research Of HIPIB Irradiation On Materials

It is of scientific importance to study the fundamental mechanisms of interaction between materials and the high-intensity pulsed ion beam (HIPIB), which is also an efficient tool for surface engineering. In the present work, the thermo-effects of HIPIB irradiation were simulated, the mechanisms of HIPIB irradiation were researched experimentally, some mechanisms are concluded and a few process plans are given. The results are as follow:The research results of numerical and experimental studies on the thermodynamical effects of HIPIB were reviewed. The effects of C⁺ and H⁺ implantation into iron target were simulated by SRIM code. The thermo-effects of HIPIB irradiation on GH3030, 45^# steel and TC4 were simulated. The results indicate that: The range of H⁺ ion is longer than that of C⁺ ion with the same energy; lots of vacancies would be formed in the subsurface areas of the targets as a result of the ion implantation; the heating rate of the 45^# target surface may reach 8.8×10¹⁰℃/s during irradiation; the cooling rate of the liquid phase of the 45^# target surface may reach 1.4×10¹⁰℃/s after irradiation.Ingot iron and 45^# steel sample targets were irradiated by HIPIB generated from TIA-450 accelerator, the beam parameters were: 70%C⁺+30% H⁺, pulse width of 50-80ns, accelerating voltage of 200-400kV, current density of 170-200A/cm²; SEM, XRD, TEM, etc. were applied to investigate the sample targets, the experimental results are as follow:Fast melting and resolidification occurred on the surfaces of the targets and craters were formed; craters could be blurred or diminished by successive HIPIB shots; the explosive eruption in local subsurface areas is the main cause of craters.The surface microhardness of ingot iron targets was improved by HIPIB irradiation; the hardening rate would be slowed; the ingot iron targets were strengthened by HIPIB; the surface microhardness of 45^# steel targets was improved after 1 shot and then decreased and stabilized as the shot number increases; the prequenched 45^# steel targets were annealed after multi-shots of HIPIB; the surface microhardness of the zones with craters is higher than those without crater due to the stress wave field generated by explosive eruptions.The density of dislocations in ingot iron targets were increased; dislocation nets, dislocation walls, dislocation cells and subgrains were formed as the shot number increased; density of dislocations in local areas of ingot iron targets were decreased after multi-shots of HIPIB; the density of dislocations in prequenched 45^# steel targets were relatively lower than the original state; preferred orientations were formed in ingot iron and 45^# steel targets irradiated by HIPIB, which might be caused by stress waves and directional solidification; the structures of the targets were refined by repeated stress waves.Nano-crystalline and amorphous structure were formed in local areas on surfaces of both ingot iron and 45^# steel targets by fast melting and resolidification.Under present experimental condition, the surface morphology of the samples could be homogenized and the structure could be refined or changed into amorphous state after 10-20 shots; it is possible to refine the surface structure of 45^# steel samples without decreasing the strength significantly.