Pulsed electron-beam technology for surface modification of metallic materials

Abstract

This article concerns the foundations of a new technology for surface modification of metallic materials based on the use of original sources of low-energy, high-current electron beams. The sources contain an electron gun with an explosive-emission cathode and a plasma anode, placed in a guide magnetic field. The acceleration gap and the transportation channel are prefilled with plasma with the use of spark plasma sources or a low-pressure reflected discharge. The electron-beam sources produce electron beams with the parameters as follows: electron energy 10–40 keV; pulse duration 0.5–5 μs; energy density 0.5–40 J/cm2, and beam cross-section area 10–50 cm2. They are simple and reliable in operation. Investigations performed with a variety of constructional and tool materials (steels, aluminum and titanium alloys, hard alloys) have shown that the most pronounced changes of the structure-phase state occur in the near-surface layers quenched from the liquid state, where the crystallization front velocity reaches its maximum. In these layers partial or complete dissolving of second phases and formation of oversaturated solid solutions and ordered nanosized structures may take place. This makes it possible to improve substantially the electrochemical and strength properties of the surface layers. It has been established that the deformation processes occurring in the near-surface layers have the result that the thickness of the modified layer with improved strength properties is significantly greater than that of the heat-affected zone. Some examples of the use of low-energy, high-current electron beams for improving the performance of materials and articles are given.

Suppression of electron emission from metal electrodes : LDRD 28771 final report.

“…Diamond polishing gave R a ~ 0.05 µm, and 2000 grit silicon carbide sandpaper R a ~ 0.08 µm. The E-fields calculated with the Electro [39] computer code for 5 to 6.4 mm gaps with 12-cm-diameter electrodes are shown in Fig. 3.…”

Динамика Импульсного Магнетронного Разряда В Сильноточной Электронной Пушке

“…Источники нерелятивистских (10−30 keV) сильноточ-ных (10−25 kA) импульсных (2−4 µs) электронных пуч-ков (НСЭП) со взрывоэмиссионным катодом и плазмен-ным анодом на основе сильноточного отражательного (пеннинговского) разряда (ОР) представляют большой интерес для поверхностной обработки материалов и уже нашли достаточно широкое применение [1][2][3][4]. В то же время ряд вопросов их формирования и транспортиров-ки изучен пока недостаточно, несмотря на то что иссле-дованию физики и техники сильноточных электронных пучков посвящено огромное количество оригинальных работ и целый ряд монографий [5][6][7].…”

Amorphous layer formation in Al86.0Co7.6Ce6.4 glass-forming alloy by large-area electron beam irradiation

“…A high-energy (0.5-1.5 MeV) scanning electron beam irradiation process has also been used to generate the amorphous phase in Zr and Cu [15] based bulk alloy. Large area pulsed electron beam (LAEB) irradiation [16] is an emerging surface modification technique. LAEB has the same advantages as other high energy beams, including high cooling rate, short process time and limited affect on the substrate.…”