Selective surface purification via crater eruption under pulsed electron beam irradiation

Zou, Jianxin; Zhang, Kemin; Chen, Dong; Qin, Ying; Hao, Shuai; Grosdidier, Thierry

doi:10.1063/1.2234306

Cited by 98 publications

(76 citation statements)

References 16 publications

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“…This indicates that a selective surface purification or homogenisation occurred. This reaction, which was observed previously under the melting mode, was triggered here without melting of the FeAl matrix 6 . This can be done through preferential selective melting of the impurities that were sputtered away from surface under the following pulses.…”

supporting

confidence: 57%

“…It is well established that improved surface properties (hardness, corrosion resistance) can be obtained by this treatment when the top surface is melted and rapidly solidified (10 7 K/s) 3,4 . This is essentially the result of ultra-fine grains formed from the highly undercooled melt 5 , melt surface purification 6 as well as strain hardening induced by the thermal stresses and shock waves 7 .…”

mentioning

confidence: 99%

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Grain Refinement and Improved Hardness/Corrosion Balance by Pulsed Electron Beam Surface Treatment of a FeAl Alloy

Zou

Stein²,

Boulanger³

et al. 2007

3rd France-Russia Seminar

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Abstract:In the present work, it is demonstrated that significant surface modifications can be generated by a low energy, high current pulsed electron beam (LEHCPEB) treatment under the so called 'Heating mode' without surface melting. Using electron back scattering diffraction (EBSD) and transmission electron microscopy (TEM) observations, it is shown that the extremely fast thermo-mechanical cycles generate grain refinement and the formation of vacancies in the surface layer which account for a significant increase of the surface microhardness of a Fe 40at%Al alloy. Comparatively, the polarisation curves measured in 0.5 M H 2 SO 4 solution indicate that the LEHCPEB treatment without melting does not change the corrosion behaviour. Keywords: Low Energy, High Current Pulsed Electron Beam; FeAl; Grain refinement; Corrosion resistanceAs is well known, the failure of industrial materials usually starts from their surface, especially when the working environment is corrosive or the applied load is moving. Therefore, it is often necessary and effective to improve the global properties of industrial materials by using surface modification techniques. During the past decades, pulsed energetic beams, such as laser, ion and electron beams, have attracted much attention in the field of materials surface modifications. Among these pulsed beam surface modification techniques, the surface treatment by Low Energy High Current Pulsed Electron Beam (LEHCPEB) has been initially developed at the Tomsk Intense Current Research Institute 1-3 . It is well established that improved surface properties (hardness, corrosion resistance) can be obtained by this treatment when the top surface is melted and rapidly solidified (10 7 K/s) 3,4 . This is essentially the result of ultra-fine grains formed from the highly undercooled melt 5 , melt surface purification 6 as well as strain hardening induced by the thermal stresses and shock waves 7 .In this work, we demonstrate the effectiveness of the LEHCPEB treatment for materials modification without melting of the top surface. This approach is of the outmost importance to get the full potential of this surface treatment technique 8 . In order to study the typical effects induced by HCPEB treatment under the so called "heating mode", a FeAl intermetallic alloy was selected in the present work. It is one of the potential candidates to replace steels for weight saving applications.The oxide dispersed strengthened (ODS) B2 Fe (40at%)Al alloy was hot extruded at 1250 o C from milled powers (with 1% Y 2 O 3 ) in the form of a rounded bar 9 . The specimens for the HCPEB treatment were cut perpendicularly to the extrusion axis into thin disks. Thus, the sample normal direction (ND) is parallel to the extrusion axis. The HCPEB treatments were carried out using a "Nadezhda-2" source 1,3 , with parameters including : accelerating voltage; 27kV, energy density; 3J/cm 2 , number of pulses; 5 and 20, pulse duration; 1.5 s, dwell time between pulses; 10s.

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supporting

confidence: 57%

mentioning

confidence: 99%

Grain Refinement and Improved Hardness/Corrosion Balance by Pulsed Electron Beam Surface Treatment of a FeAl Alloy

Zou

Stein²,

Boulanger³

et al. 2007

3rd France-Russia Seminar

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“…Indeed, it has been clearly established that the redissolution of carbides or second-phase particles in the melted layer of HCPEB-treated samples brings a more homogeneous microstructure having enhanced corrosion resistance properties. [30] Another interesting observation revealed in this work is the presence of the mixed <100> + <110> fiber texture in the rapidly solidified c layer. The texture development can be influenced at the two stages controlling the solidification process that starts by nucleation and continues with growth.…”

Section: Discussionmentioning

confidence: 90%

Texture and Microstructure at the Surface of an AISI D2 Steel Treated by High Current Pulsed Electron Beam

Zou

Grosdidier

Bolle

et al. 2007

Metall Mater Trans A

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Surface modifications were investigated for an AISI D2 steel after 25 pulses of high current pulsed electron beam (HCPEB) treatment. In particular, X-ray diffraction (XRD) was used to determine the thickness, nature of phase, and texture in the top surface melted layer. The mechanisms responsible for the structure and texture evolutions were further asserted by scanning electron microscopy (SEM) and electron backscattering diffraction (EBSD) results. Under the action of the beam, the large carbides present in the steel were melted and dissolved so that the top surface rapidly solidified as a 3-lm-thick layer of ultra-fine-grained metastable austenite without any martensite formation. The growth of the c phase led to an unusual <100> + <110> fiber solidification texture. In addition, R3-twin boundaries were observed to bridge, most often, near <110> domains. These features, observed here in a Fe supersaturated and highly undercooled melt, are discussed in light of recent findings on atypical growth in directionally solidified Al-based alloys. [40][41][42] Comparatively, the a phase present in the heataffected zone remained randomly oriented.

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“…В частности, пока-зано, что на облучаемой поверхности образца из нержавеющей стали местами возникновения микрократеров являются места расположения частиц сульфида марганца (MnS). Для образцов из никелида титана характерно появление микрократеров на местах расположения частиц интерметаллида NiTi 2 [2]. Поскольку материал включений второй фазы имеет теплофизические свойства, отличные от свойств материала матрицы, то его присутствие будет оказывать влияние на распределение температуры в области расположения включения.…”

Section: да шепель аб марковunclassified

“…Наличие градиентов температуры приводит к термокапиллярной конвекции, что, в свою очередь, является наиболее вероятной причиной возникновения кратеров на поверхности материалов [4][5][6][7]. Из литературы известно, что в результате облучения на поверхности образца из нержавеющей стали 316L доля образующихся кратеров составляет 0.25, это означает, что четыре включения дают один кра-тер [2]. На поверхности образца из никелида титана доля образующихся кратеров составляет приблизительно 0.07, т. е. почти в 4 раза меньше, чем для стали.…”

Section: да шепель аб марковunclassified

Распределение Температуры В Образце С Микроскопическим Включением Второй Фазы При Облучении Низкоэнергетическим Импульсным Сильноточным Электронным Пучком

Шепель¹,

Марков²

2017

Письма В Журнал Технической Физики

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С помощью методов численного моделирования рассчитано температурное поле, возникающее в поверхностном слое мишени из никелида титана, содержащей включения интерметаллида NiTi2, облучаемой низкоэнергетическим сильноточным электронным пучком микросекундной длительности. Полученное температурное поле сравнивалось с температурным полем, рассчитанным ранее для мишени из нержавеющей стали 316L, содержащей включение из сульфида марганца (MnS). Обнаружено, что, как и в случае с нержавеющей сталью, в области расположения включения существует перегрев. Однако величина перегрева в случае никелида титана (12 K) существенно ниже, чем в случае нержавеющей стали 316L (283 K). Также существенно отличается динамика плавления двух систем. DOI: 10.21883/PJTF.2017.03.44221.16301

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Selective surface purification via crater eruption under pulsed electron beam irradiation

Abstract: Articles you may be interested inFormation and evolution of craters in carbon steels during low-energy high-current pulsed electron-beam treatment J.Ti surface alloying of an AISI 316L stainless steel by low energy high current pulsed electron beam treatment

Cited by 98 publications

References 16 publications

Grain Refinement and Improved Hardness/Corrosion Balance by Pulsed Electron Beam Surface Treatment of a FeAl Alloy

Grain Refinement and Improved Hardness/Corrosion Balance by Pulsed Electron Beam Surface Treatment of a FeAl Alloy

Texture and Microstructure at the Surface of an AISI D2 Steel Treated by High Current Pulsed Electron Beam

Распределение Температуры В Образце С Микроскопическим Включением Второй Фазы При Облучении Низкоэнергетическим Импульсным Сильноточным Электронным Пучком

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