钨渗铜燃气舵加工表面条纹分析

以钨渗铜燃气舵(牌号W-7Cu)为研究对象,对产品在机加工过程中出现的若干宽约1～2 mm的带状条纹进行分析.结果表明,机加工表面的条纹是钨经高温烧结后产生的一种局部钨骨架致密化的组织形态;现有无损探伤检测无法检出该条纹缺陷,条纹不属于无损检测认定的内部缺陷;条纹的存在对局部强度有影响,但对整体性能的影响不大,性能均满...     

燃气舵用钼渗铜连接板超声波探伤不连续显示分析

以燃气舵系统中使用的钼渗铜(牌号Mo-10Cu)连接板为研究对象,对产品在超声波探伤过程中发现的不连续显示现象进行分析。结果表明,钼渗铜产品超声探伤标注的带状区域(不连续显示区域)存在直径约2～5μm的微孔,微孔是造成超声波探伤不连续显示的根本原因。带状区域与非带状区域,组织几乎相同,力学性能相近;并提出了针对钼渗铜产品超声波探伤进行分级的建议。     

某钨渗铜燃气舵装配过程断裂原因分析

以某型号钨渗铜燃气舵(牌号W-7Cu)为研究对象,针对产品在装配过程出现的断裂现象进行分析.结果表明:断裂方式以穿晶断裂为主,沿晶断裂并存;断口和其他部位的微观组织无明显区别;应力集中是导致材料断裂的原因,提出了加强对连接位置的防护或结构改进,避免应力集中造成破坏的建议.     

钨渗铜喉衬加工表面颜色异常分析

针对钨渗铜W-7Cu加工的喉衬产品表面出现颜色异常的现象,选取原材料棒材余料和颜色异常的喉衬两种样品,对样品物理性能、无损探伤、金相组织、力学性能及显微形貌进行对比分析。结果表明,两者无明显或本质的异常,排除了材料造成颜色异常的可能性。加工工艺也是影响产品结构和性能的重要因素,因此重新设计了转速为700～800 r/min,扣刀前角为0°～6°,后角为0°～8°的工艺参数,加工的新产品整体颜色光亮无异常,为后续钨渗铜喉衬的制备及质量控制提供相应的参考。     

钼粉粒度均匀性对钼渗铜材料组织的影响

采用熔渗法制备了钼渗铜材料。采用超声波探伤的方法对钼渗铜材料进行了无损检测，采用SEM和金相分析对钼渗铜材料进行了微观组织观察，分析了钼粉的粒度均匀性对钼渗铜钼材料组织的影响。研究结果表明：粉末粒度均匀性对钼骨架的渗铜性能有影响；粉末中存在的细颗粒较多或者有粉末团聚现象时，钼骨架局部细小孔隙聚集，铜难以渗入这些聚集的小孔隙，造成超声波探伤渗铜均匀性不佳；超声波探伤发现的“面积型渗铜不均”实际是“密集微孔聚集”。     

熔铸-扩散法制备黄铜/钨铜功能梯度材料的研究

对用熔铸-扩散法制备的黄铜，钨铜功能梯度材料进行了研究，对界面区域的元素成分分布和微观组织结构进行了分析，对界面区域的电导率、结合强度及抗脉冲大电流损伤性能进行了测试。结果表明：用该法制备的黄铜，钨铜功能梯度材料，界面区域由成分和组织渐变的三层结构组成；电导率在界面区域呈渐变分布趋势，没有出现电导率突变现象；这种结构缓解了因热性能不匹配而造成的热应力，提高了黄铜与钨铜合金的结合强度；界面的抗脉冲大电流损伤性能良好。     

W-Cu材料室温强度和组织均匀性的影响因素

用浸透法对孔隙度为12%～17%的烧结钨进行了渗铜试验 ,研究了影响低铜含量的W -Cu材料室温бb及渗铜组织均匀性的因素 ,研究结果表明 ,铜对钨骨架的强化和韧化机制对提高W -Cu材料的室温бb 有重要作用 ;钨骨架具有合适的孔隙度是W -Cu材料获取均匀一致的渗铜组织的重要条件。     

钨骨架湿氢烧结工艺研究

为了降低钨骨架的烧结温度和提高钨铜复合材料的性能,采用湿氢烧结工艺制备钨骨架,对湿氢烧结-熔渗法制备的W—15Cu钨铜材料性能进行研究,并对钨的湿氢烧结机理进行探讨。采用扫描电镜（SEM）和X射线衍射仪（XRD）对钨骨架和钨铜复合材料的组织与成分进行观察与分析,并测定材料的密度、气密性、热导率和热膨胀系数（CTE）。结果表明：在1450℃下湿氢烧结2h,钨骨架发生较明显的烧结收缩和致密化。用该钨骨架制备的钨铜材料的各项性能均达到热沉材料的要求。湿氢烧结机理主要是在湿氢条件下,通过反复进行的氧化与还原使金属粉末表面形成激活能较低的新生态原子,从而使烧结温度降低。     

钢铁研究总院的三项钨材和一项硬质合金科研成果通过技术鉴定

<正> 1988年12月,冶金部钢铁研究总院在北京市有三项钨材和一项硬质合金科研成果通过技术鉴定,它们是钨基复合燃气舵材料、钨镍铜高压触头合金、钨锡助熔剂和陀螺仪转子轴尖专用硬质合金。其中,钨基复合燃气舵材料和轴尖专用硬质合金系由冶金部和航空航天部共同主持鉴定的鉴定项目。钨基复合燃气舵材料用于大型固体燃料战术导弹,要求能经受高温高速并带有固体微粒的燃气流的强烈烧蚀和冲刷作用,因此要求高的高温强度、表面硬度和抗热震性,研制的技术难度大。但是,课题组全体同志见难而上,研制成钨基复合燃气舵材     

钨渗铜复合材料致密化机理研究

以粗细钨粉和铜丝为原料,采用粉末冶金工艺制备钨骨架,随后通过液态熔渗铜的方法制备低铜含量(质量分数低于10%)的钨渗铜复合材料。利用电子天平、金相显微镜和扫描电镜分析材料的致密度及显微组织,对材料在制备过程中的致密化机理进行探讨。结果表明:钨渗铜复合材料熔渗过程的驱动力既有毛细管力又有晶界扩散作用,熔渗路径可用根系模型来阐释;在钨骨架中加入Ni等诱导金属可强化熔渗过程;低铜含量的致密钨渗铜复合材料需制备高致密度且具有联通晶界或孔隙的钨骨架。     

粉末粒度对于高温钨渗铜材料骨架性能的影响

高温钨渗铜材料是由高温烧结钨骨架经熔渗金属铜而制成的互不固溶型复合材料 ,钨骨架的连续程度、钨颗粒的连接状态以及孔隙形态和大小等因素将直接影响材料的使用性能。本文从钨粉粒度的角度出发 ,研究其对于钨渗铜材料骨架性能的影响 ,实验表明 ,在相同的烧结制度 (2 2 30℃× 5h)下 ,细颗粒钨粉所得到的骨架密度比中颗粒钨粉所得到的要高 ,但其内部形成大量封闭孔隙 ,使得其连通性能不及中颗粒钨粉所得骨架 ,不利于金属铜的熔渗 ;对于相近骨架密度 (86± 0 5 % )的两种试样 ,从渗铜结果来看 ,二者的骨架连通性能相当。从SEM照片来看 ,细颗粒钨骨架的晶粒尺寸明显比同骨架密度中颗粒钨骨架的晶粒尺寸小 ,高温拉伸结果显示细颗粒钨渗铜材料比相应中颗粒钨渗铜材料的强度要高的多 ,这一点说明了钨骨架的晶粒细化对钨渗铜材料有明显的强化作用。     

Fusion welding of steel powder metallurgical preforms to wrought copper

Abstract

The present paper reports the feasibility studies on joining low density steel powder metallurgical (PM) preforms with wrought copper. In joining of these materials by tungsten inert gas (TIG) welding, the welding current, pulse frequency and the density of the PM preforms were found to have a strong influence in controlling the weld strength. When welded with lower welding currents (continuous current), copper infiltrated into the PM steel and with higher currents, thermal effects dominated in controlling the weld strength. Through the application of a pulsed current, grains became more equiaxed due to dendrite fragmentation. Microstructural refinement was found to be at a maximum at an optimum pulse frequency, which resulted in maximum tensile strength.     

钨铜合金表面粗糙度对抗电弧烧蚀性能的影响

将纯W、纯Cu和W70Cu30合金分别进行机械磨光、电解抛光和机械抛光后获得3种不同的表面状态,在专有设备上模拟电触头材料的电弧烧蚀过程,通过扫描电子显微镜观察首击穿烧蚀形貌。结果表明:通过机械抛光获得的表面粗糙度最小,对于W70Cu30合金可达到0.044μm,电解抛光次之,机械磨光最大;随表面粗糙度降低,W70Cu30合金的击穿场强逐渐增大,烧蚀区域趋于规整化,烧蚀产物增加,烧蚀坑的分布更加集中,纯W、纯Cu也表现出相同的现象;在本实验条件下材料表面粗糙度在0.2~0.3μm时,其抗电弧烧蚀性能最好。     

真空开关和电子器件用钨铜材料

随着真空开关和电子器件新应用的开发，发展了钨铜材料的新系列—真空钨铜材料。本文介绍了真空钨铜材料的特点、制取工艺及主要性能，并讨论了与应用有关的问题。     

铜瓦铸件铸造工艺设计探讨

用文字和工艺设计简图阐述了各类材质和相应大小铜瓦铸件的铸造生产工艺，并总结了造型和熔炼过程中容易导致铜瓦铸件产生黑皮、气孔、缩孔和裂纹缺陷甚至报废的关键工艺控制措施。     

两种不同配方材质对铜熔浸影响的比较

介绍了两种不同配方的铜熔浸材料（ＦｅＣｕＺｎ和ＦｅＣｕＭｎ）在铜熔浸中的不同效果，比较了熔浸后产品的性能。     

The effect of tungsten particle size on the processing and properties of infiltrated W-Cu compacts

Three tungsten powders with average particle sizes of 8.7, 23.2, and 65.2 μm were used to make W-15Cu compacts. The compacting pressure and sintering temperature were adjusted for each powder to attain the desired skeleton density. Sintered skeletons were then infiltrated with oxygen-free copper at 1200 °C in hydrogen and in vacuum. Results showed that as the tungsten particle size decreased, higher compacting pressures and sintering temperatures were required for the same desired skeleton density. The processing parameters and the tungsten particle size caused variations in the amount of closed pores and the W-W contiguity, which in turn resulted in different infiltrated densities and resistivities. Direct infiltration on green compacts was also examined, and higher infiltration densities and lower electrical resistivities were obtained compared to those obtained by infiltrating sintered compacts. These results are discussed based on infiltrated density, differences in microstructure, and the W-W contiguity.     

超高温雾化制备球形铸造碳化钨粉末形貌控制及性能研究

传统的热喷涂用碳化钨粉末通常采用铸造方法生产,粉末呈多角状,流动性差且硬度低,难以满足高性能硬面材料的要求。以钨粉、炭黑、碳化钨粉前躯体或多角状碳化钨为原料,采用自行设计的超高温熔炼及超高温雾化装备制备出球形碳化钨粉末,利用扫描电镜、X射线衍射仪、金相显微镜、显微硬度计分析测试了粉末的相、组织、成分及性能。结果表明:碳化钨粉末外观呈球状、内部为细针状共晶组织、显微硬度3 200 HV、霍尔流速6.5 s/50 g、具有流动性好、耐磨性佳等优良的综合性能。     

Analysis of Metallurgical and Mechanical Properties of Continuous and Pulsed Current Gas Tungsten Arc Welded Alloy C-276 with Duplex Stainless Steel

The present work investigates the microstructure and mechanical properties of alloy C-276 fabricated by continuous and pulsed current gas tungsten arc welding process and by employing ER2553 filler wire. Optical and scanning electron microscopic analyses were carried out to study the microstructures of weldments produced. Energy dispersive X-ray spectroscopy (EDS) was performed to investigate the formation of secondary phases in the weldments. The results disclosed that pulsed current gas tungsten arc welding showed refined microstructure compared to continuous current gas tungsten arc welding. SEM/EDS analysis revealed the segregation of Mo in the weld interface regions in both the welding techniques. The extent of microsegregation reduced the strength and toughness of the weld joint compared to the base metal. Bend test revealed cracks in the weld interface region in both the weldments.     

Investigation of sintered properties on infiltrated tungsten–copper composite along the infiltration direction

Tungsten–copper composites exhibit excellent resistance to erosion and good electrical as well as thermal conductivity. W–Cu composites are mainly used for heat sinks, electrical contacts and transpiration cooling applications. In this investigation the microstructure, mechanical and electrical properties of infiltrated tungsten–copper composite along the infiltration direction have been studied. The microstructures of the top, middle and bottom regions of the composite were evaluated using both optical and scanning electron microscope. Bulk hardness, electrical conductivity, instrumented hardness and contiguity were measured along the depth of W–Cu composite. It was found that the copper phase fraction decreases along the infiltration direction of the specimen. The effect of distribution of copper in the W–Cu system has a significant influence on the mechanical and the electrical properties. The effect of copper content on indentation depth, instrumented hardness, Young’s modulus, and stiffness of the composite has been evaluated using an instrumented hardness tester.