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。     

强流脉冲电子束处理下40Cr的摩擦磨损性能研究

利用强流脉冲电子束对40Cr钢进行表面改性处理,分析了处理后的金属组织、表面硬度、截面硬度、表面粗糙度以及摩擦磨损性能.结果表明,不同加速电压下摩擦系数的变化受材料照射前表面粗糙度状况、照射后熔坑的形貌和分布密度的影响,此外,电子束照射引起的材料表面组织的变化也会使摩擦系数发生改变,随电压的增大材料的耐磨性提高.     

脉冲偏压对304不锈钢表面多弧离子镀CrAlN薄膜结构和耐蚀性能的影响

目前,鲜见有关脉冲偏压对多弧离子镀Cr Al N薄膜耐蚀性能影响的报道。以不同的脉冲偏压在304不锈钢表面多弧离子镀Cr Al N薄膜。采用扫描电镜、显微镜、X射线衍射仪、硬度仪、粗糙度仪分析了Cr Al N薄膜的表面形貌、相结构、硬度、表面粗糙度及耐蚀性能,分析了脉冲偏压对相关性能的影响。结果表明:随着脉冲偏压幅值的增大,Cr Al N薄膜表面大颗粒及凹坑尺寸和数量减少,薄膜质量提高;Cr Al N薄膜主要由(Cr,Al)N相组成,随着偏压增加,Cr Al N薄膜出现(220)择优取向;Cr Al N薄膜表面粗糙度随脉冲偏压增大而减小,显微硬度随脉冲偏压的增大而增大;Cr Al N薄膜在3.5%Na Cl溶液中的耐蚀性随着脉冲偏压的增大而增大,脉冲偏压为400 V时,Cr Al N薄膜与基体304不锈钢的腐蚀速率之比为0.34,薄膜的综合性能最好。     

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.     

Research State of High Current Pulsed Electron Beam Surface Treatment

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.     

微观组织对0Cr17Ni4Cu4Nb马氏体不锈钢的耐点腐蚀性能的影响

采用化学浸泡法和模拟闭塞电池方法研究了固溶+时效和固溶+调整+时效处理的0Cr17Ni4Cu4Nb马氏体不锈钢的耐点腐蚀性能,并与18-8型奥氏体不锈钢(316L)耐点蚀性能进行了对比。结果表明,0Cr17Ni4Cu4Nb马氏体不锈钢组织内富Cu析出相促进了点蚀坑萌生,而点蚀坑发展则与组织形貌有关。固溶+调整+时效处理的0Cr17Ni4Cu4Nb马氏体不锈钢因组织内析出富Cu相多而大,其萌生的点蚀坑密度较高,但由于马氏体板条较细,其点蚀坑尺寸和深度较小;固溶+时效处理的0Cr17Ni4Cu4Nb马氏体不锈钢因组织内析出富Cu相少而小,萌生的点蚀坑密度较低,但粗大的板条马氏体组织导致点蚀坑尺寸和深度较大。与18-8型奥氏体不锈钢耐点蚀性能对比表明,通过对0Cr17Ni4Cu4Nb马氏体不锈钢进行合理的热处理,其耐点蚀性能可与18-8型奥氏体不锈钢相当。     

AZ31镁合金强流脉冲电子束表面改性研究

通过动电位极化曲线测试.光学电子显微镜及电子探针等方法研究了强流脉冲电子束表面处理对AZ31镁合金腐蚀性能的影响及样品的表面形貌与成分.结果表明,在5%NaCl溶液中,加速电压27kV、脉冲8次处理后的样品比原始样品耐蚀性提高了1.6倍;处理后样品的表面出现了典型的熔坑形貌;电子束快速凝固过程使最表层晶粒细化,进而导致表层镁、铝元素含量及分布形式发生变化.样品表层铝元素含量的提高是改善其耐腐蚀性能的主要原因.     

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。     

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.     

Mechanisms of hardening, wear and corrosion improvement of 316 L stainless steel by low energy high current pulsed electron beam surface treatment

The mechanisms of corrosion and wear improvements by low energy high current pulsed electron beam (LEHCPEB) have been investigated for an AISI 316 L steel. Selective purification followed by epitaxial growth occurred in the top surface melted layer (2-3 μm thick) that was softened by tensile stresses and, to a much lower extent, by lower efficiency of MnS precipitation hardening. Electrochemical impedance spectroscopy and potentiodynamic polarization analyses used to model the corrosion behavior revealed that, while craters initiated at MnS inclusions initially served as pitting sites, the resistance was increased by 3 orders of magnitude after sufficient number of pulses by the formation of a homogeneous covering layer. The wear resistance was effectively improved by sub-surface (over 100 μm) work hardening associated with the combine effect of the quasi-static thermal stress and the thermal stress waves. The overall results demonstrate the potential of the LEHCPEB technique for improving concomitantly the corrosion and wear performances of metallic materials.     

旋耕刀表面强流脉冲电子束改性后的耐磨性研究

为了提高农机零部件的主要磨损部件旋耕刀的耐磨性,延长其使用寿命,采用强流脉冲电子束表面改性技术处理旋耕刀常用材料60Si2Mn钢表面.采用金相显微镜分析形貌,通过显微硬度对比和摩擦磨损分析处理表面的性能,优选加速电压,将其作为优化参数作用于旋耕刀表面,并在土槽台架模拟工况试验.结果表明:电子束表面改性技术可以有效提高旋耕刀的耐磨性,对侧刃内侧处理要优于对侧刃外侧的处理;加速电压为30 kV和27 kV时,旋耕刀表面耐磨性较优,前者的磨损量较小.     

强流脉冲离子束辐照对45钢表面状态的影响

本文研究了强流脉冲离子（HIPIB）束辐照对45钢表面形貌、显微硬度及残余应力等影响。结果表明,经HIPIB辐照处理,45钢表面出现火山口状熔坑,5次脉冲处理时熔坑比较明显,试样表面也变得凹凸不平,随着脉冲次数的增加,熔坑之间会连成不规则的网状形貌且界限变得不明显,表面发生光化。试样的显微硬度随着脉冲次数的增加而提高,未辐照时,显微硬度为HV342,20次脉冲时达到HV911。经HIPIB辐照处理,试样表面产生残余拉应力,且随着脉冲次数的增加,样品表面残余应力增大,由未处理时的152 MPa提高到656MPa。     

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.     

Enamel coating for protection of the 316 stainless steel against tribo-corrosion in molten zinc alloy at 460℃

Hot-dip galvanizing provides excellent corrosion and wear resistance for steels.However,the equipment itself,such as the steel roller,immerged in corrosive molten zinc suffers serious material loss during steel's production.Its protection has become the main technique problem in modern galvanizing line.In this study,an enamel coating was designed and prepared.Its tribo-corrosion in molten zinc alloy(Zn-0.2 wt%Al)at 460℃was investigated in comparison with the traditional WC-12 Co composite coating and the 316 stainless steel.Results indicate that the steel suffers serious material damage.Various corrosion products of Fe₂ Al₅ Znx form at the worn surface and the wear scar has reached 200μm deep after merely 5 h tribo-corrosion.Though the two coatings provide an improved tribo-corrosion resistance,for the WC-12 Co coating,its chemical reaction with the molten zinc increases brittleness and promotes cracking.The synergistic wear and corrosion cause its degradation.The enamel coating performs better during tribo-corrosion.It is chemically stable in molten zinc thus able to provide high corrosion resistance.In addition,the amorphous[Si04]network and the self-lubricating CaF₂ crystallite help it to build up an intact amorphous glaze layer readily at surface on sliding,leading to a reduced wear loss.During the whole tribo-corrosion process,the enamel coating is completely free of cracking,and the Zn penetration is inhibited.     

The observation of unipolar arc damage on stainless steel and TiC coatings on stainless steel

Unipolar arcing represents a plasma-surface interaction process leading to surface damage and metal impurity influx in tokamaks. It develops if the sheath potential formed in the plasma-surface contact is high enough to ignite and sustain a micro-arc. A laser-produced plasma was used for a comparison of the arc damage produced on stainless steel surfaces with that on surfaces protected with a coating of TiC a few microns thick. Smooth coatings of superior-quality TiC were produced by the activated reactive evaporation process, which is a plasma-assisted physical vapor deposition process. For a sufficiently high electron temperature in the laser-produced plasma a large number (about 300 000 cm^?2) of unipolar arc craters were observed on the stainless steel surface which had been exposed to the expanding laser-produced plasma cloud for a few hundred nanoseconds. In comparison, no similar arc craters were detected on the surfaces protected by the TiC coating which showed minimum damage limited to the laser beam impact area.     

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.