The Study On The Mechanism And Changes Of Morphology Surface Irradiated By High Current Pulsed Electron Beam

The"SOLO"electron source had been applied to the high-steel (W18Cr4V), titanium and iron; the typical morphology and structural changes of the sample surface had been analyzed by OM, SEM, TEM and XRD in this work. Deposition and distribution of the enegy were studied from an experimental point of view; and the mechanism of the formation and evolution of the craters on different materials'surface according to the deposition and distribution of the enegy and crystal melting characteristics; the variation of the surface morphology irradiated by different the current, voltage and the number of pulses was revealed in the last section. The main experimental findings were as follows:1. It was found that the electron beam energy would give priority to distribute or deposit to the metal surface and the interface phase of the materials treated by different pretreatments under the effect of the electron back-scattering, electron diffraction and electron energy deposition patterns in the process of the irradiation.2. On the basis of the uneven melting crystals, and the distribution and deposition of the beam energy, the interface would melt firstly, and then, erupt in the fact of the quasi-static stress in the irradiation of the high current pulsed beam electron (HCPEB). For a specific material, the order of the eruption was that the second phase particles (the craters caused by the uneven of the closed phase interface on the surface of the high-steel) , small grain (ones induced by the melting of the grain boundary on the iron) and the boundaries (ones on the titanium) from easy to difficult. And the morphology of the craters were changed as the different materals.3. Metal surface morphology and its variation were determined by the energy deposited. The ennergy deposited could be changed by the current, voltage and the number of pulses of the pulsd electron beam. As the energy deposited increased, they proper sequence appear that were geometrical defect ablation, the emergence and disappearance of the craters, the formation of the flat surface with stripes deformation. Typical morphology, such as cell-like morphology, micro-cracks, multi-ring craters, sag, shrinkage and so on, would appear as the result of the craters.