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钼及钼合金粉末冶金技术研究现状与发展 总被引:1,自引:0,他引:1
系统总结了钼及钼合金粉末冶金技术的研究进展和工业应用现状。分别论述了钼粉末冶金理论、超细(纳米)钼粉、大粒度(和高流动性)钼粉、高纯钼粉、新型钼成型技术、新型钼烧结技术、钼粉末冶金过程数值模拟技术等7个研究方向的技术原理、技术特点、设备结构和工业应用现状,并分析其发展前景。 相似文献
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系统总结了钼合金及其粉末冶金技术的研究进展和工业应用现状。分析了钼材料脆性产生的两大原因:本征脆性和间隙杂质在晶界上的富集。系统论述了钼金属的主要强韧化技术的作用机制及发展现状。依次论述了钼粉末冶金理论、超细(纳米)钼粉、超大钼粉、高纯钼粉、新型钼成型技术、新型钼烧结技术等钼粉末冶金技术的原理、特点和工业应用现状,并分析了其发展前景。 相似文献
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试验研究了掺杂La2O3、Y2O3、CeO2稀土氧化物颗粒对钼合金的粉末物性、烧结进程、制品的烧结致密度及压力加工丝材的室温力学性能的影响规律。试验结果表明,掺杂稀土氧化物粒子细化了钼粉的粒度,降低了松装密度和粒度分布范围,同时导致粉末团聚现象增多;稀土氧化物粒子延迟了钼合金的烧结进程,降低了烧结制品的致密度,同时细化了烧结体晶粒尺寸。稀土氧化物粒子以弥散强化和细晶强化的形式,提高了钼合金丝的室温强度。CeO2显著提高了钼合金丝的室温韧性,La2O3、Y2O3则降低了钼合金丝的室温韧性。 相似文献
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本文研究了La2O3对钼烧结坯力学性能的影响。将纯钼及不同La2O3含量的ODS钼合金在1500℃和2050℃真空退火后,测试其力学性能。结果表明,添加La2O3后,无论是轧制状态还是高温退火后,材料的抗拉强度均显著高于相同加工状态的纯钼。La2O3强化钼合金的再结晶温度显著提高,因此具有优异的高温性能,从而改善了材料从高温加热回复至室温的低温脆性。 相似文献
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Molybdenum is usually fabricated through the powder metallurgy (P/M) process, using fine powders with a relatively high oxygen
content. Oxygen, however, is one of the main elements causing embrittlement during the deformation processing of molybdenum,
such as rolling, extrusion, and forging. Thus, how to deoxidize the compact as completely as possible is critical in the P/M
process. This study shows that, as an alternative to hydrogen reduction, molybdenum oxides can be reduced by adding organic
lubricants to the compact and by sintering the compact under high vacuum with long sintering times. After 10 hours of sintering
at 1750 °C and a 0.03 torr vacuum, the oxygen content decreased from 0.927 wt pct of the green compact to 0.017 wt pct. The
ductility also improved significantly compared to compacts sintered for 5 hours, which contained 0.218 wt pct oxygen. The
morphology evolution, weight changes, and the X-ray analysis indicated that the oxide was first present in the form of MoO3. It was then transformed into MoO2 before deoxidation was completed. Two deoxidation mechanisms were identified: evaporation and decomposition of MoO3 and MoO2, with evaporation being dominant in the early-stage sintering and decomposition being dominant in the later stage. 相似文献
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N. Senthilnathan A. Raja Annamalai G. Venkatachalam 《Transactions of the Indian Institute of Metals》2017,70(5):1161-1176
Tungsten is a refractory metal possessing good mechanical properties of high strength, high yield point, and high resistance to creep. Therefore, tungsten and its alloys are used in many high temperature applications. Due to the high melting point, they are generally processed through powder metallurgy method. The powders are compacted using die pressing or isostatic pressing. The compacts are sintered in a sintering furnace to achieve high density, thereby, making the metal suitable for further processing. This article reviews the recent research findings of consolidating tungsten and its alloys (W–Ni–Fe and W–Ni–Cu), from preparation of powder alloys to sintering of the compact. The advances in sintering are based on the objective of achieving good densification of the metal at lower temperature and at faster rate. The use of microwave sintering and spark plasma sintering techniques resulted in significant reduction in sintering time and producing products of good mechanical properties. 相似文献
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在钼钛锆(titanium zirconium molybdenum alloy,TZM)合金粉末中分别添加质量分数为0、0.25%、0.50%、1.00%的HfC粉末颗粒,利用粉末冶金结合轧制变形的方法制备多元复合强化钼合金。通过金相组织观察、扫描电子显微镜形貌表征、能谱分析以及力学性能测试等手段,研究了HfC颗粒对TZM合金显微组织和力学性能的影响。结果表明,添加HfC颗粒可以抑制TZM合金晶粒在烧结过程中的长大,但添加量超过0.50%时,抑制效果减弱。当HfC颗粒质量分数为0.25%时,TZM合金的室温和高温抗拉强度最强,维氏硬度最高,塑性最优。 相似文献
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采用粉末冶金方法制备含Y2O3的稀土钼合金,利用金相显微镜、扫描电子显微镜(SEM)、X射线衍射(XRD)、能谱分析(EDS)等手段对钼合金的断裂特征和组织结构进行对比分析,研究稀土氧化物Y2O3含量对钼合金组织和性能的影响.研究表明:添加Y2O3能细化晶粒、改善钼合金的晶粒均匀性和致密度、提高钼合金的性能:拉伸强度和屈服强度随Y2O3含量的增加呈现先增高后降低的趋势,在Y2O3含量为1%时,抗拉强度达511.43MPa,屈服强度456.99MPa,分别是纯钼材料的1.31倍和1.57倍,综合力学性能最佳;在烧结坯中,Y2O3颗粒分布均匀,主要以球形和等轴状形式存在于晶界上. 相似文献
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以-200目电解铜粉和雾化细黄铜粉为原料, 利用喷撒烧结设备、拉伸成锥设备及模具, 研究了铜基粉末冶金双锥同步器同步环的撒粉烧结和拉伸成锥工艺。结果表明, 铜基粉末冶金摩擦材料的孔隙率保持在30%左右, 且孔隙呈细微和均匀分布; 摩擦材料层的平均动摩擦系数为0.081, 静摩擦系数为0.146, 磨耗率为8.70×10-9 cm3/J; 该材料在随钢芯板冷拉伸成锥形时不掉渣, 厚薄均匀, 锥度、圆度及尺寸变化很小, 其原料配方和拉伸成锥工艺可适用与大批量生产。 相似文献
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Dopant particle characterization and bubble evolution in aluminum-potassium-silicon-doped molybdenum wire 总被引:1,自引:0,他引:1
L. E. Iorio B. P. Bewlay M. Larsen 《Metallurgical and Materials Transactions A》2002,33(11):3349-3356
The present article describes the creation of dopant inclusions in aluminum-potassium-silicon (AKS)-doped molybdenum powder
and the generation of potassium bubbles in doped molybdenum wire. Molybdenum wire is used extensively in the incandescent
lamp industry for coiling mandrels, filament support wires, and foil seals. The AKS-doped molybdenum wire is an important
product, because it possesses greater high-temperature strength and a higher recrystallization temperature than undoped molybdenum;
both of these properties are important for structural applications in lamps. The AKS-doped molybdenum wire is produced in
a similar manner to AKS-doped tungsten wire, but lower processing temperatures are typically used for the production of molybdenum
wire. Previous studies on AKS-doped tungsten wire have shown that the dispersion which provides the interlocking grain structure
in recrystallized tungsten wire is bubbles of elemental potassium; these enhance incandescent lamp filament life. However,
there is little previous work on the potassium-containing dispersion in AKS-doped molybdenum wire. In AKS-doped molybdenum,
the dispersion can be either potassium bubbles, or solid oxide particles, depending on the processing method. This article
will describe a series of analyses of doped molybdenum wire and its precursors, namely, doped powder and sintered ingots.
The roles of high- and low-temperature sintering are also described. 相似文献
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AbstractThe conventional powder metallurgy (PM) approach of compaction and sintering has been used extensively in the fabrication of tungsten alloys and composite hardmetals based on WC-Co. In fact, these are some of the earliest known materials to have been fabricated by the PM route. The last 15-20 years have seen the emergence of a new shaping technique of powder injection moulding (PIM) which can shape such tungsten metal alloys and composites into complex near net shaped components. The PIM process starts with the mixing of an organic binder with the desired powders in the form of a homogeneous mixture, known as a feedstock. The feedstock, like plastics, can be moulded into near net shapes from which the organic part is removed and then the material can be sintered to almost theoretical density. This produces complex, near net shaped parts that have properties that are comparable to that of the press and sintered materials. This paper will provide a brief overview of the use of PIM in tungsten based alloys and composites and discuss some of the applications of these materials. 相似文献
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从PM2004看世界粉末冶金的发展现状 总被引:6,自引:0,他引:6
详细介绍了2004年粉末冶金世界大会的基本情况, 概述了国际粉末冶金工业现状, 并按照类别阐述了粉末冶金各技术领域以及材料产品, 如粉末烧结钢、粉末注射成形、粉末制备技术、粉末压制技术、粉末烧结理论与技术、粉末多孔材料、硬质合金、粉末轻金属、粉末零件后续处理加工技术、粉末冶金过程模拟与标准化以及粉末功能材料等的发展趋势。世界粉末冶金的发展现状和趋势表明粉末冶金技术是工业化集成技术, 而不仅仅是一种高技术。 相似文献