等离子喷涂氧化铝涂层界面状态和结合性能的研究

采用相同的等离子喷涂工艺参数对TC4钛合金、45钢、6061铝合金和纯铜等不同基材进行了等离子喷涂工艺试验.利用金相显微镜和扫描电镜观察了涂层组织的界面结合状态,测试了不同基材上涂层的结合强度,分析了基材性质不同对涂层残余应力、界面组织状态和结合强度性能的影响规律.结果表明:基材的热膨胀系数、导热系数、比热容等物性参数...     

Pb1-Q245R爆炸焊接复合板结合界面研究

采用电阻测量装置、金相显微镜、透射电镜对爆炸焊接铅-钢复合板结合界面进行了研究.结果表明,铅-钢复合板结合界面导电性能优越;界面结合形态呈准正弦波形,无漩涡区;结合界面两侧的铅元素和铁元素相互扩散,钢侧铅含量降低较快,铅侧铁含量降低较慢,扩散的深度在微米数量级;结合界面组织由铁微晶与铅微晶混合组织组成.     

铝/钢爆炸复合界面的显微分析

通过金相显微镜与电子探针对铝/钢复合板的界面进行了显微分析.结果表明,铝、钢爆炸复合过程中不易形成波状界面,复合界面呈平直状,界面处金属发生了冶金反应;爆炸焊接过程中,铝/钢复合界面处的基体金属发生了熔化,界面处的晶粒发生了严重的塑性变形,并且在铝/钢直接结合的界面两侧存在着距离约为5μm的扩散.分析认为爆炸焊接的工艺特点及铝、钢的物理性质决定了铝/钢界面的显微特点.并据此探讨了影响铝/钢复合强度的因素.     

梯度复合SiC/C面向等离子体材料的制备与表征

利用粉末冶金方法,完成了SiC和C两种难烧结物质的同步烧结,制备出了SiC成分分布从0％～100％的接近理论密度的SiC/C FGM,显微观察显示材料的成分和结构是呈梯度分布的。材料将SiC的良好的耐腐蚀性和石墨的良好的抗热冲击性结合在一起,并具有较高的有效热导和良好的抗热疲劳能力,化学溅射和Tokamak原位等离子体辐照结果显示材料具有良好的耐高温等离子体冲刷性能。     

Metallurgical and Corrosion Properties of Explosively Welded Ti6Al4V/Low Carbon Steel Clad

Titanium alloy (Ti6Al4V) and Iow carbon steel (LCS) were joined by explosive welding method using different ratios of explosive. Some metallurgical properties of joined samples were investigated. Joined samples were examined by means of optical microscope, scanning electron microscope (SEM) and tensile-shearing tests. Bending, tensile, hardness and corrosion behaviour of the samples were investigated. Separation was not occurred on the joining interface after tensile-shearing and bending tests. It is seen that hardness of both plates were increased with increasing explosive.It is found that increasing explosive ratio leads to an increase in corrosion. It is also found that corrosion rate was high at the beginning of the experiment but the rate of the corrosion decreased subsequently during the experiment.     

Metallurgical and Corrosion Properties of Explosively Welded Ti6A14V/Low Carbon Steel Clad

1.IntroductionIn order to join metals preserving their propertiesand to join metals having different properties,solid-statewelding methods are used[1].Explosive welding is a solid-state process in which controlled explosion forces to jointwo or more materials together under high pressures[2~5].It is used to joint directly a wide variety of similar or dis-similar metals that cannot be joined by any other weld-ing or bonding technique[6~8].The parameters of thesystem include:(1)the explosive cha…     

等离子体清洗同步辐射光学元件

同步辐射光束线的光学元件的碳污染问题.它导致光学系统的光通量下降,尤其是在碳吸收边情况更加严重.因此在光束线运行一定的时间后,必须对光学元件的碳污染进行清洗以便保证其正常使用. 为此我们开发了一套射频等离子体原位光学元件清洗系统,以干燥的氧气和氩气为介质.在产生的等离子中存在大量的臭氧,与光学元件表面的碳反应,变成CO和CO_2气体,从而达到清洗的目的.实验证明等离子体清洗不但可有效清除碳污染,而且有利于光束线真空系统的超高真空环境的恢复,为光束线的维护提供了方便.     

梯度复合B_4C/Cu面向等离子体材料的制备与表征

基于Ｂ４Ｃ和Ｃu材料具有明显电阻率及熔点差的特点,提出了在超高压下通电快速烧结Ｂ４Ｃ／Ｃｕ梯度复合材料的新工艺．在 ２～４ＧＰａ、１２ｋＷ,４０ｓ及适当的热处理条件下成功制备出了成分分布从０～１００％的接近理论密度的Ｂ４Ｃ／Ｃu层状复合材料;显微观察显示材料的成分和结构是呈梯度分布的．化学溅射实验表明其产额比 ＳＭＦ ８００核纯级石墨降低 ７０％;在Ｔｏｋａｍａｋ原位等离子体辐照下,材料表面无明显损伤．     

钛-不锈钢复合棒等强结合的特性

钛-不锈钢复合棒是航空航天领域中一种金属新材料,其性能的可靠性是保证各类航天器安全运行的重要条件,在工艺优化条件下生产的钛-不锈钢复合棒,具有与母材钛强度相等的结合强度,进一步证实了"爆炸焊接金属的极限强度等于或大于母材金属中较弱者的强度"这一说法.文章从金相、拉剪强度及钛材性能改变方面分析复合棒的显著特点,说明等强结...     

Modifying the Properties of Tungsten Based Plasma Facing Materials with Single-Wall Carbon Nanotubes

Tungsten is one of the best candidates for plasma-facing components in fusion reactors owing to its unique properties. But disadvantages such as its brittleness and high ductile-to-brittle transition temperature have restricted its fusion energy application. Single-walled carbon nanotubes （SWCNTs） have the potential to be used as reinforcements due to their excellent mechanical properties. A new method of modifying the properties of tungsten by doping with SWCNTs was introduced. An efficient way of dispersing SWCNTs into the tungsten matrix with strong interfaces by heterocoagulation and ultrasonication was employed, and hot explosive compaction （HEC） technology was selected to compact and sinter the composite powders. The sintering properties, microstructure, densification effect, thermal conductivity, hardness and fracture toughness of the obtained SWCNTs/W bulk samples were tested, and compared with pure tungsten. The influences of SWCNTs on these properties and the main toughening mechanism of SWCNTs in a tungsten matrix were discussed.     

钨用作核聚变装置面对等离子体材料可行性分析

通过与碳材料比较,分析钨作为核聚变面对等离子体材料的可行性。研究结果显示,钨是最有前景的面对等离子体材料,氢及其同位素滞留量小、热能和粒子反射率高、溅射率低、杂质聚集可控等,除此之外,钨具有熔点高、热力学性能优异等优点。     

Plasma spray of biofunctional(Mg,Sr)-substituted hydroxyapatite coatings for titanium alloy implants

Plasma-sprayed hydroxyapatite(HA) coatings have been widely utilized in load-bearing titanium alloy implants. In this study, Mg, Sr co-substituted HA((Mg, Sr)-HA) nano-scale powders have been synthesized, which are further used to prepare(Mg, Sr)-HA coatings on Ti-6 Al-4 V alloys in order to improve the biological functions. The average size of(Mg, Sr)-HA nano particles is ～75 nm. The average bonding strength for(Mg, Sr)-HA coating and samples after heat treatment at 500°C or 600°C for 3 h are26.17 ± 2.11 MPa, 36.07 ± 4.48 MPa and 37.07 ± 2.95 MPa, respectively. There is a significantly increase of bonding strength likely due to low residual stress after heated treatment. MC3 T3-E1 cells show a high proliferation rate when cultured with(Mg, Sr)-HA coating extract compared to the normal culture medium, which also exhibit large extension and deposition of extracellular matrices when adhered on the coating surfaces. Thus, these(Mg, Sr)-HA coatings show high bonding strength and improved biological functions, which offer promising future applications in the fields of orthopedics and dentistry.     

聚变堆中面向等离子体材料的研究进展

受控热核聚变能是公认的可以有效解决人类未来能源需求的主要途径之一,经过多年的努力,其研究已经取得很大进展,进入了从物理可行性向工程可行性的验证阶段.决定核聚变能未来发展的一个关键问题是相关的材料问题,尤其是面向等离子体材料的发展.评述了国内外目前核聚变实验装置中面向等离子体材料的研究进展.     

梯度复合B4C/Cu面向等离子体材料的制备与表征

基于B4C和Cu材料具有明显电阻率及熔点差的特点,提出了在超高压下通电快速烧结B4C／Cu梯度复合材料的新工艺。在2－4GPa,12kW,40s及适当的热处理条件下成功制备出了成分分布从0－100％的接近理论密度的B4C／Cu层状复合材料;显微观察显示材料的成分和结构是呈梯度分布的。化学溅射实验表明其产额比SMF800核纯级石墨降低70％;在Tokamak原位等离子体辐照下,材料表面无明显损伤。     

冷压焊界面结合机理与结合强度研究现状EI北大核心CSCD

固相焊接因其突出的技术优势在先进金属结构材料焊接中获得越来越多的应用。冷压焊作为一种特殊固相焊接方法,其界面结合机理和结合强度预测是长期以来困扰研究者的两大难题。本文综述了冷压焊界面结合机理理论研究现状,重点讨论了冷压焊接头界面结合强度影响因素及其预测模型,并指出了今后冷压焊界面结合机理需综合考虑扩散、再结晶、位错等因素,同时结合强度预测模型应考虑变形程度、变形速率、变形温度等方面。     

Interface properties of aluminum/steel friction-welded components

The study of the metallurgy of the interface of metal/metal friction-welded components is essential for understanding the quality of bonding. We have studied, through optical and electron microscopy, and tensile strength measurements, the bonding properties of Al and interstitial free steel and Al and stainless steel friction-welded components. The samples were produced by varying the friction time and rotational speed, friction pressure, upsetting pressure, and upsetting time constant at optimized values reported earlier. The bonding occurs over an intermetallic phase, which, when too thick, influences the bonding properties adversely. The thickness of the intermetallic interlayer depends linearly of on the square root of the friction time, indicating that the growth is caused by diffusion. The effect of oxidation on the bonding is also studied on samples prepared under argon atmosphere and normal atmosphere.     

聚变堆装置中面向等离子体材料钨涂层的研究进展

钨具有高的熔点、不与氚发生共沉积、与等离子体好的兼容性和低的腐蚀率等优点,是最有前景的一种面向等离子体材料.为了解决面向等离子体材料的制备及其与热沉材料连接问题,涂层技术在实验聚变堆装置中得到广泛应用.评述了目前实验聚变堆装置中面向等离子体材料钨涂层的研究进展.     

Neutron computed tomography of plasma facing components for fusion experiments

In nuclear fusion experiments, divertor plates are used to remove energy and particles from the plasma. These divertor plates can be made of water-cooled copper heat sinks covered by carbon fiber composite (CFC) protection tiles. During operation, surface temperatures in excess of 1000 °C are reached for typical heat loads of 10 MW/m². The large mismatch in the coefficients of thermal expansion for CFC and Cu causes high stresses and possibly bonding defects. Growing joint defects, which lead to unacceptable overheating of the protection tiles, are critical for the lifetime of the components.A prototype component was subjected to 10,000 cycles at 10 MW/m² to study the crack growth mechanism. Neutron computed tomography offers the possibility to analyze such structures on centimeter-sized samples non-destructively with a high spatial resolution. At the ANTARES neutron imaging facility of the FRM II reactor, the samples were loaded with a contrast agent and examined with neutron computed tomography.     

层状复合材料界面结合强度非传统评价方法

简要总结了层状复合材料界面结合强度的非传统评价方法。非传统界面结合强度评价方法包括:波振法(激光层裂法、应力波法、超声波法、电磁波法)、划痕法(激光划痕法)、辅助分析法(X射线衍射法、有限元法、解析法)和其他方法(电阻法)。波振法是将载荷以冲击波的形式施加在界面位置处,实现复层和基体分离。划痕法是将高能激光作用于复层,分离界面,实现界面结合强度的测量。电阻法通过建立界面电阻和界面强度之间的关系,评价界面结合强度。与传统界面评价方法对比,非传统评价方法有特殊优点:对材料的破坏程度小,有效抑制材料的弹塑性变形,测得界面强度接近界面本征强度。但非传统法也仍存在一些亟待解决的问题,随着新材料的不断出现,需要不断改进现有测试方法,使界面结合强度评价方法向着简单易行、无损、自动化的方向发展。