电子束熔覆工艺对合金表面改性的研究现状

在电子束熔覆改性中,加工工艺对基体的熔覆层造成较大影响.为得到最优熔覆层性能,需要寻找最优的熔覆层成分、工艺参数、加工顺序.综述了不同加工工艺对电子束熔覆层的微观组织结构、表面力学性能的影响,分析总结出迭代优化熔覆工艺的途径.展望了电子束熔覆表面改性研究的发展前景.     

电子束表面合金化研究进展

阐述了电子束表面合金化的基本原理及国内外电子束合金化设备的应用和发展.介绍了强流脉冲电子束表面合金化做为一种新型表面合金化方法在研究领域的应用,并综述了近年来电子束表面合金化研究的发展动态,简述了国内外相关领域的主要研究成果及取得的进展.对电子束表面合金化技术做出了展望,指出合金层的定量控制,电子束与表层金属间的热力耦...     

镍基合金电子束熔覆表面改性及高温耐磨性研究

利用电子束在Inconel 617高温合金表面熔覆WC-CoCr复合涂层,设计正交试验分析了工艺参数对熔覆层的影响,研究了优化后涂层的组织与性能.结果表明,电子束扫描束流对熔覆质量特性影响最为显著,优化工艺下获得的熔覆层与基体合金相互扩散并形成良好的冶金结合,熔覆层内出现了WC、CoCr、(Fe,Ni)C6、Fe3W3...     

表面熔覆技术的研究进展

综述了表面熔覆技术的发展概况,介绍了几种常见熔覆方法的工艺特点及应用现状,并从熔覆层组织、裂纹敏感性及耐磨性三方面阐述了熔覆层的研究成果.概述了金属基复合材料的优良性能及基体与增强体的选择.指出表面熔覆技术应以熔覆层组织性能稳定为研究重点,兼顾熔覆工艺的简单化、成本低廉化,同时促进原位自生法的理论基础研究.最后指出表面熔覆技术的研究方向及目前需解决的问题.     

电子束熔覆WC-CoCr涂层的表面结构以及耐磨性

镍基合金在含氯介质中有着优异的耐蚀性能,但其耐磨性不足。本文首先利用HVOF在Inconel617基体上沉积WC--CoCr涂层,研究了经过电子束重熔获得新的改性层表面形貌以及相成分。电子束处理后,一些喷涂层的结构缺陷得到了改善,涂层空隙减少,晶粒得到了细化,由于生成了高硬度的新相（尤其是Co6W6C相）,熔覆层的显微硬度为1100HV0.3,为基体显微硬度（550HV0.3）的两倍。通过摩擦磨损实验分析,试样相比于基体的滑动磨损行为,其磨损率有着显著的降低,而EDS分析表明,熔覆层内出现了新的元素,基体与涂层达到了良好的冶金结合。此外,熔覆层在盐水中的抗腐蚀能力有所提高。     

激光熔覆技术在钛合金表面改性中的应用

激光熔覆是现代表面改性制造技术中的一种极有发展前途的高新技术.激光熔覆技术在钛合金表面改性方面得到了广泛的应用,通过激光熔覆技术,可显著改善钛合金的表面耐磨性.针对激光熔覆技术在钛合金表面改性方面的应用发展,概述了近年来国内外利用激光熔覆技术改善钛合金表面性能的研究与应用现状,并对激光熔覆技术进一步的发展领域及发展方向进行了展望.     

表面高频感应熔覆涂层技术

感应熔覆技术与其他表面改性技术相比,具有许多独特的优点,应用越来越广泛.简要介绍了高频感应熔覆技术及其基本原理,重点介绍了感应熔覆技术的发展状况、工艺流程及其影响因素和控制方法,并展望了感应熔覆技术的发展趋势.     

激光熔覆技术研究进展

激光熔覆技术是一种先进的材料表面改性技术,具有稀释率小、熔覆层组织致密、涂层与基体结合良好及工作环境无污染等优点。从激光熔覆喷头、激光熔覆工艺、激光熔覆材料、激光熔覆技术的工业应用这4个方面,综述了激光熔覆的研究进展。其中,在激光熔覆喷头方面,介绍了激光光斑的种类及转换原理和熔覆材料的引入方式,总结了激光束与粉束的耦合模式和熔覆喷头的种类,包括旁轴送粉熔覆喷头、光外同轴送粉喷头、光内同轴送粉喷头以及特殊工况下的熔覆喷头。在激光熔覆工艺方面,阐述了工艺参数对熔覆层宏观形貌和组织性能的影响,总结了激光熔覆复合工艺的辅助加工方法,论述了超高速激光熔覆新工艺的原理及技术优势,并介绍了激光熔覆过程控制的研究进展。在激光熔覆材料方面,阐述了熔覆材料的种类及增强相的添加方式。在激光熔覆技术的工业应用方面,介绍了激光熔覆技术在矿山机械、模具再制造以及铁路修复等领域的应用。最后对激光熔覆技术的发展趋势及应用前景做出了展望。     

铝合金表面激光熔覆研究现状

总结了铝合金表面激光熔覆的特点,评述了铝合金表面激光熔覆技术的处理工艺和熔覆体系的研究现状,分析了各种熔覆层的组织特征及性能,阐明了铝合金激光表面熔覆存在的主要问题和改进途径,并提出了今后的任务.     

强流脉冲电子束表面处理

以T8钢、D2模具钢和AZ91HP镁合金为试验材料,利用强流脉冲电子束(加速电压为27 keV,脉冲持续时间约为1 μs,能量密度约为2.2 J/cm2)在试样表面进行辐照处理,研究了处理试样的表层组织、相结构及性能变化规律.另外,结合电子束能量沉积过程中瞬时温度和应力的作用特点,详细讨论了表面熔坑及深层硬化现象的形成机理.     

Surface modification of Al-Pb alloy by high current pulsed electron beam

Al-Pb alloy was modified by high current pulsed electron beam and the microstructure, hardness and tribological characteristics were characterized by scanning electron microscopy, electronic microanalysis probe microanalysis, Knoop hardness indentation and pin-on-disc type wear testing machine. The results show that the microstructure and hardness can be greatly improved, and the modification layer consists of a molten zone, an overlapped zone of heat-affected and quasistatic thermal stress-affected zone and a transition zone followed by the substrate. The tribological properties of high current pulsed electron beam irradiated Al-Pb alloy are correspondingly improved largely. Optical observation and scanning electron microscopy analysis reveal that the low wear rate and lowest level in coefficient of friction at high load level for irradiated Al-Pb alloy are due to the formation of a lubricious tribolayer covering the worn surface, which is a mixture of Al2O3, Pb3O4 and silicate. The wear mode varies from oxidative wear at low load to film spalling at high load and, finally, adhesive wear.     

TA15钛合金强流脉冲电子束表面改性

研究强流脉冲电子束(HCPEB)处理TA15钛合金的表层组织和耐蚀性能变化.结果表明,样品表面凹凸不平,最外表面有2～3 μm的单一α′马氏体重熔层,次层为3～5 μm的热影响区.在5%NaCl溶液中进行动电位极化曲线测定,经5次脉冲处理样品的腐蚀速度最小.经强流脉冲电子束处理的TA15合金表层晶粒细小,成分均匀,有利于形成致密的钝化膜,增大极化电阻,降低腐蚀速度.     

Microstructure refinement and alloying of WC-CoCr coatings by electron beam treatment

The corrosion and wear behaviour of HVOF (high velocity oxygen fuel) sprayed WC-CoCr (cermet) coatings were investigated before and after electron beam (EB) remelting. In this regard, the coatings were deposited on INCONEL 617 substrate. The mentioned Ni-based alloy is well known for its good corrosion behaviour in chloride containing media but exhibits not enough good wear properties.The paper investigates the influence of EB-remelting process on sliding wear respectively on corrosion resistance in 1 M NaCl solution of the alloyed surface. Scanning electron microscopy (SEM) and X-Ray Diffraction (XRD) were performed before respectively after the EB-treatment in order to investigate the coating morphology as well as the phase modification achieved through the alloying process. Tribological tests concerning the sliding wear behaviour of the tested materials revealed a significant decrease of the wear rate for both the as-sprayed coating respectively the alloyed surface in comparison with the base material. However, the as-sprayed cermet coating exhibits the lowest wear rate among the investigated samples.The microhardness of the alloyed surface was higher (1100 HV₀₃) in comparison with that of the as-sprayed cermet coating (905 HV₀₃) as a result of new phase formation (especially the η-Co₄W₂C). The corrosion behaviour in salt water of the EB remelted surface was also considerably improved in contrast to the as-sprayed cermet coating.     

Surface modification of polyurethane and silicone for therapeutic medical technics by means of electron beam

Surface modification technologies are gaining growing acceptance for treatment of implant materials to enhance biocompatibility. Our examinations focus on polyetherurethane and silicones, two typical flexible implant materials, which we have modified by non-thermal electron beam processing. Advantages of this method are the adjustable degree of modification as well as the simultaneous sterilizing effects.The polymer surfaces were characterized with regard to wetting behavior, surface energy, chemistry and morphology. The cell adhesion was examined too. The results reveal that the electron beam is a useful tool for surface modification of polymers.     

纳米Fe-Al粉电子束改性铝合金的组织和性能

利用电子束扫描技术对铝合金ADC12表面进行纳米合金化处理,探讨电子束扫描技术对铝合金组织和性能的影响;通过添加不同比例的纳米Al-Fe混合粉末,分别用扫描电子显微镜(SEM)、EDAX能谱仪(EDS)、X射线衍射仪(XRD)等设备对合金层的组织、物相构成、硬度以及摩擦磨损性能进行分析测试,确定合金化纳米混合粉的最佳配比.结果表明:电子束纳米Al-Fe合金化可以提高铝合金材料的硬度、增加耐磨性;随着混合粉中纳米Fe粉含量的增加,合金层中合金硬质强化相逐渐增多,合金化层的硬度和耐磨性也逐渐提高,硬度最高可达800 HV,但组织中会出现裂纹且均匀性不好.当混合粉中纳米Fe粉含量为50％时,合金化层的硬度和耐磨性能较好,其耐热硬度,在675 K时硬度可达到300 ～ 400 HV,其磨损量仅为铝合金基材的1/6.     

Surface modification of TC4 Ti alloy by laser cladding with TiC+Ti powders

Laser surface cladding was applied on a TC4 Ti alloy to improve its surface properties.Mixed TiC and Ti powders with a TiC-to-Ti mass ratio of 1:3 were put onto the TC4 Ti alloy and subsequently treated by laser beam.The microstructure and composition modifications in the surface layer were carefully investigated by using SEM,EDX and XRD.Due to melting,liquid state mixing followed by rapid solidification and cooling,a layer with graded microstructures and compositions formed.The TiC powders were completely dissolved into the melted layer during melting and segregated as fine dendrites when solidified.The inter-dendritic areas were filled with fine α' phase lamellae enrich in Al.Mainly due to the reduced TiC volume fraction with increasing depth,the hardness decreases with increasing depth in the laser clad layer with a maximum value of HV1400,about 4.5 times of the initial one.     

铌合金电子束表面熔覆层裂纹控制

在铌合金表面进行了电子束熔覆硅化物涂层试验.利用光学显微镜(OM)、扫描电镜(SEM)观察了涂层表面形貌,通过分析熔覆层表面的裂纹率以及裂纹的最大宽度,对熔覆涂层质量进行评价,研究了电子束熔覆参数对裂纹的影响.结果表明,裂纹倾向随着电子束束流、聚焦电流及扫描速度的增大呈先减小后增大的变化规律,通过控制电子束熔覆参数的合理匹配可以实现对涂层裂纹的控制.通过单变量试验和正交优化试验,筛选出了优化的熔覆处理工艺参数为:电子束束流为17 mA,聚焦电流为1 885mA,扫描速度为540 mm/min.采用优化工艺参数获得的涂层的熔覆效果较理想,表面平整光滑无裂纹,晶粒致密均匀.