强流脉冲电子束对4Cr13不锈钢的表面改性

为了改善4Cr13不锈钢的表面强度和耐磨性,对其进行了强流脉冲电子束表面辐照处理,研究了该处理对4Cr13的形貌、相结构、显微硬度及耐磨性能的影响。结果表明：电子束处理后,不锈钢表面出现多种形态的熔坑,20次脉冲处理时熔坑边缘出现了大量的变形孪晶;脉冲电子柬处理使不锈钢发生了由α相向γ相的转变,表层晶粒细化至纳米尺度;...     

强流脉冲电子束FV520B钢表面改性组织及耐腐蚀性能

利用强流脉冲电子束进行FV520B钢表面改性,处理参数包括加速电压27 k V,能量密度5 J/cm2,脉冲次数1到25次。使用扫描电镜、电子探针和X射线衍射分析样品表层形貌、元素分布和相组织变化。经强流脉冲电子束改性后,样品表面形貌细密均匀,晶粒尺寸降至2μm以下,重熔层厚度约4μm并形成沿(200)择优方向的柱状凝固组织。样品表层深约10μm范围内的沉淀硬化颗粒得到有效溶解,成分分布均匀化。在3.5%(质量比)Na Cl溶液中测试电化学腐蚀性能,25次脉冲处理样品的腐蚀电位由原始样品的-0.213 V升至0.038 V,腐蚀速率降低约一个数量级。     

纯镁强流脉冲电子束表面改性及合金化研究

强流脉冲电子束是一门新兴的表面处理技术。本文利用强流脉冲电子束对纯镁进行表面改性,并尝试表面合金化铝处理。利用光学显微镜、扫描电镜和透射电镜对表面处理层形貌和组织结构进行了分析,同时也进行了摩擦腐蚀性能测试。纯镁强流脉冲电子束表面改性后,显微硬度得到明显提高;纯镁表面合金化铝后,样品抗5％NaCl溶液腐蚀性能得到显著提高,维钝电流密度降低2个数量级以上,同时也对相关改性机理进行了初步分析。     

模具钢SKD11强流脉冲电子束表面处理的形貌研究

利用强流脉冲电子束不同工艺参数对模具钢SKD11进行表面处理,发现处理表面出现典型的熔坑形貌。通过金相显微镜、电子探针成分分析、三维形貌轮廓仪对处理样品表面进行分析,模具钢SKD11亚表层碳化物的喷发是熔坑形成的主要原因。熔坑的分布情况与电子束处理工艺参数密切相关。在相同加速电压下,熔坑面密度随脉冲处理次数的增加而减少,而熔坑平均尺寸呈现先随脉冲次数增加到最大值而后减小的趋势;对于相同处理次数时,使用高加速电压的样品表面形成的熔坑面密度较低,而且要比低电压更快地进入到平稳阶段。表面粗糙度呈现随着脉冲次数的增加而降低的现象。     

镁合金强流脉冲电子束表面改性

选用变形镁合金AZ31和铸造镁合金AZ91HP作为研究对象,进行强流脉冲电子束表面处理研究,这种处理能够有效地提高镁合金的抗蚀性和达到表面强化效果.处理后样品表面呈起伏形貌,出现典型熔坑,重熔层4 μm～10μm,导致表面出现塑性变形,主要是孪晶形式.由于镁的蒸发和第二相Mg17Al12熔化,表面形成铝的过饱和固溶体.性能测试主要是摩擦磨损和抗腐蚀性能测试.近表层几百微米范围内均出现显微硬度值升高的现象,改性样品平均摩擦系数降低,耐磨性提高.处理后样品在5%NaCl溶液中抗腐蚀性能有显著提高,镁合金强流脉冲电子束处理后,铝固溶度增加,表面易于形成致密的氧化膜,动电位极化曲线测量结果显示极化电阻增大,自腐蚀电流降低,最大可降低三个数量级,极化电阻与之相反.     

强流脉冲电子束辐照AZ91镁合金表面组织及磨损性能研究

利用强流脉冲电子束进行AZ91铸造镁合金表面辐照改性,处理参数包括加速电压27 k V,脉冲次数1到30次。使用金相显微镜、扫描和透射电子显微镜观察样品表层形貌和显微组织。研究表明,原始铸造组织的粗大树枝晶α-Mg和颗粒相β-Mg17Al12发生熔解,表面成分均匀化,并形成细小的复合纳米网状结构。改性AZ91镁合金的表面显微硬度和耐磨损性能得到显著提高,8次脉冲处理样品的表面显微硬度由原始62.7 HK提高到119.4 HK,磨损速率由0.01126降至0.00173mm3/min。     

AM50镁合金强流脉冲电子束表面改性的研究

采用强流脉冲电子束（HCPEB）对含稀土的AM50镁合金进行表面改性处理。利用金相显微镜、扫描电镜和显微硬度计等对试样的截面和表面进行观察,研究了强流脉冲电子束表面改性对其摩擦磨损性能及耐腐蚀性能的影响。结果表明：处理层的截面组织经脉冲电子柬轰击后发生了很大的变化;从表面形貌可以看出存在许多弥散分布的微米尺度的熔坑;显微硬度测试结果表明,处理层的硬度比基体的硬度明显提高;耐磨性及耐腐蚀性能均较基体提高,同时在不同处理参数下耐磨性及耐腐蚀性能有所不同。     

交流脉冲等离子体改性聚四氟乙烯的XPS研究

用交流脉冲等离子体对聚四氟乙烯进行了表面改性实验.利用XPS研究了处理后样品表面的化学成分、电子结构和结合能.结果表明:交流脉冲等离子体作用于聚四氟乙烯样品表面将发生C-F键断裂,表层氟含量减少,氧含量增加;由于大量极性基团的引入,使得PTFE亲水性能得到改善.同时讨论了不同交流脉冲占空比对改性效果的影响,占空比较大时改性效果更佳.     

HCPEB表面处理的研究现状

强流脉冲电子束(HCPEB)表面处理是一种新兴的高能束表面处理技术.综述了脉冲电子束处理,表面熔坑的形成机制及熔坑、弥散颗粒、裂纹、波状起伏、条形纹理、胞状晶等典型形貌影响因素和演变规律方面的研究成果,总结了表层结构变化与表面显微硬度、耐磨性、耐蚀性能等改性工艺的研究现状,并认为扩大强流脉冲电子束应用范围和系统的探究是目前研究的重点.     

HCPEB表面处理的研究现状

强流脉冲电子束(HCPEB)表面处理是一种新兴的高能束表面处理技术.综述了脉冲电子束处理,表面熔坑的形成机制及熔坑、弥散颗粒、裂纹、渡状起伏、条形纹理、胞状晶等典型形貌影响因素和演变规律方面的研究成果,总结了表层结构变化与表面显微硬度、耐磨性、耐蚀性能等改性工艺的研究现状,并认为扩大强流脉冲电子束应用范围和系统的探究是目前研究的重点.     

Morphology and phase modification of HVOF-sprayed MCrAlY-coatings remelted by electron beam irradiation

The electron beam remelting process is one of the most convenient processes to reduce the disadvantages of thermal-spray coatings. The effect of high-energy electron beam irradiation on surface remelting and microstructural modification in MCrAlY coatings are investigated in this study. This surface treatment is made to modify the morphology and the phases of the coated layer in order to improve the corrosion resistance. The specimens were remelted by using a high-energy electron beam accelerator. The microstructure, corrosion resistance and phase modification were examined. Scanning Electron Microscopy, light microscopy and X-Ray Diffraction were performed to characterize the phase modification and morphology before and after the treatment.     

The effect of electron beam fusion on the structure and properties of plasma jet sprayed nickel alloy coatings

Nickel-based alloy coatings were obtained on carbon steel (steel 3) samples by means of high-velocity pulsed plasma jet spraying of PG-10N-01 and PGAN-33 commercial powders, followed by electron beam fusion of the coating and substrate. The coated samples were studied by methods of X-ray diffraction, scanning electron microscopy, and electron-beam microprobe (energy-dispersive X-ray spectroscopy) and tested for hardness, friction wear, corrosion resistance, and adhesion. It was found that the electron beam processing leads to an almost tenfold increase in the friction wear resistance, a threefold growth in microhardness (relative to that of the substrate), and a significant increase in the resistance to corrosion in acid media. The observed increase in the working characteristics is related to changes in the phase composition, grain structure refinement, and redistribution of alloy components in the substrate and film and a decrease in porosity of the coating material.     

Surface alloying by pulsed intense electron beams

Results of numerical calculations and experimental studies of the thickness of modified layers, distribution of implanted materials, microstructure and phase composition inside the layers following pulsed electron beam treatment are presented. Possible physical mechanisms of the alloying process are discussed. The improvements of surface properties, especially corrosion resistance against liquid lead, are presented. It is shown that corrosion of OPTIFER IVc steel by liquid lead containing 8×10⁻⁶ at% oxygen is avoided by alloying Al into the surface.     

Surface treatment of DZ4 directionally solidified nickel-based superalloy by high current pulsed electron beam

Surface treatment of DZ4 directionally solidified nickel-based superalloy was carried out by using high current pulsed electron beam (HCPEB) technique. Microstructure changes in modified surface layer were characterized together with their corrosion property. It is found that the treated surface becomes rougher with increasing the number of HCPEB pulse due to the formation of craters occurring preferentially in the interdendritic areas. The thickness of remelted layer increased slightly when more HCPEB pulses applied and reached about 3 μm after 10 HCPEB pulses. The corrosion resistance of modified surfaces exhibited an effective improvement when measured in 0.5 mol/L sulfuric acid solution. The factors that influence the corrosion resistance of DZ4 alloy were discussed by considering the surface purification effect featured by HCPEB surface treatment.     

Microstructure modifications and corrosion behaviors of Cr4Mo4V steel treated by high current pulsed electron beam

In this work, Cr4Mo4V steel was irradiated by high energy current pulsed electron beam (HCPEB) with energy density of 6 J/cm². Morphology and phase composition of the surface layer were analyzed using scanning electron microscopy (SEM) and glancing angle X-ray diffraction (GXRD). The crater-like morphology was observed on surface after HCPEB treatment, and the thickness of melted layer was ∼7 μm. Results from GXRD revealed that HCPEB treatment could suppress martensite transition and the content of retained austenite in the melted layer increased with irradiation number. The corrosion resistance was evaluated by electrochemical polarization tests in neutral 3.5% NaCl solution. Compared with the untreated Cr4Mo4V steel, corrosion potential of the samples treated by HCPEB improved and the corrosion current density decreased. The improved corrosion resistance is attributed to the absence of the carbide, formation of retained austenite and dissolution of alloy elements, particularly of Cr and Mo, into the matrix.     

尿素级316Lmod不锈钢管材的休氏腐蚀性能

采用休氏试验法研究了不同固溶热处理工艺对尿素级316Lmod不锈钢管材休氏腐蚀性能的影响,利用光学显微镜和扫描电镜观察了不同工艺热处理的试样在休氏试验过程中的表面腐蚀形貌,并分析了休氏试验的腐蚀机理。结果表明:在1000~1150℃下固溶热处理试样的平均腐蚀速率随固溶温度的升高而降低,而耐休氏腐蚀性能随固溶温度的升高而升高;随着腐蚀试验周期的增加,试样晶界的腐蚀坑数量增加,腐蚀坑面积增大,腐蚀速率也增大;随着固溶温度升高,相同腐蚀试验周期的试样晶界的腐蚀坑数量减少,腐蚀坑总面积也减少,耐休氏腐蚀性能提高。平均晶粒尺寸与固溶温度成正比,尺寸越大,材料耐非敏化态晶间腐蚀性能越好,耐休氏腐蚀性能也就越好。     

Elektronenstrahl‐Randschichtbehandlung für die Herstellung verschleißbeständiger Auftragschichten auf nichtrostenden Stählen

Stainless steel components exposed to mechanical stresses are subjected not only to corrosion, but to abrasive wear. There are several possibilities for enhancing the wear resistance of stainless steels; however, such processes are very often associated with a reduction in corrosion resistance. This paper presents an electron beam surface treatment technology to significantly improve the wear resistance of austenitic steels (e.g. X6CrNiMoTi17‐12‐2) and duplex steels (e.g. X2CrNiMoN22‐5‐3), without a negative influence on the corrosion behavior. Fe‐ and Co‐additive wires were deposited thermally by electron beam cladding. The cladding layers produced were free of defects such as cracks and pores, and were well metallurgical bonded to the base materials. Microstructural analysis, hardness measurements, wear tests and corrosion tests were carried out. The wear rate k was reduced by a factor of 100 compared to the base materials for electron beam cladding with Fe‐based wire and by a factor of 10 with Co‐based wire. Corrosion resistance was preserved for the Fe‐based cladding layers and slightly increased (by a factor of 3) for the Co‐based cladding layers.