粉末冶金钨钼材料发展的国内外近况

本文从钨、钼金属及其合金，高比重钨合金，钨铜类复合材料三方面介绍了国内外近年来的发展情况，讨论了应用及市场发展潜力。     

The relative effects of chromium,molybdenum, tungsten,and tantalum on the occurrence of σ phase in cast Ni-Co-Cr alloys

Chromium, molybdenum, tungsten, and tantalum have been compared with each other in regard to their influence on the occurrence of Σ phase in cast nickel-base superalloys. The compositions of the alloys were similar to the chromium-enriched matrix of alloys strengthened by λ′ precipitate, but with systematic variations in refractory-metal content. To induce precipitation of Σ phase, the alloys were aged for 3000 h at 1400?F (760?C), 1550?F (845?C), and 1700?F (925?C). Quantities of Σ phase were determined with the aid of an image-analyzing computer. On an atomic percentage basis, molybdenum, tungsten, and tantalum are equivalent with regard to the minimum concentration of each element that is necessary to cause Σ phase precipitation in 3000 h; their potency is slightly more than twice as high as that of further chromium additions above the 37.5 at. pct base chromium level. At higher refractory metal concentrations, somewhat greater quantities of Σ phase are formed by specific atomic concentrations of molybdenum and tungsten than by tantalum. Tantalum also forms large quantities of a tantalum-containing Μ phase in the as-cast ingot and a (Ni, Co)₃Ta phase on aging, the volume of all precipitate being much higher than the quantity of Σ phase for the molybdenum- and tungsten-containing alloys. At any given atomic concentration of molybdenum, tungsten, or tantalum, considerably larger quantities of Σ phase are formed than by a given increment of chromium above the 37.5 at. pct base chromium concentration in Mo-W-Ta-free alloys.     

Fabrication of alloyed aluminum nickelides by metallothermy of metals oxides

Fabrication conditions of NiAl, NiAl–Cr, and NiAl–Cr–Mo–W alloys by joint aluminothermic reduction of initial metal oxides are investigated. Thermodynamic characteristics of accompanying reactions are determined. The temperature dependence of the change in the isobaric potential (ΔG°, kJ/mol) of reduction reactions of oxides points to the high formation probability of alloys. It is revealed by differential thermal analysis that the reduction of metal oxides enters the active phase after aluminum is melted at ~650°C and progresses according to the heterogeneous mechanism in a temperature range of 800–1100°C. The optimal composition of the initial charge, which provides the maximal yield of metals into alloys, is established. It is found experimentally that the yield of metals into alloys constitutes 85–92 wt %. Synthesis products are identified by the elemental and X-ray phase analyses as intermetallics of the Ni–Al system, which contain inclusions of chromium, molybdenum, and tungsten. It is shown that the concentration of inclusions varies in a range of 1.5–6.5 wt %. The microhardness of alloys is determined to vary from 3546 to 7436 MPa, depending on the content of alloying elements.     

钨合金废料的资源再生利用技术

钨是一种稀有金属，钨合金具有高的强度、硬度，较好的耐高温性、耐密性和良好的电性能。广泛应用于航空航天工业、兵器工业、核工业、信息产业、汽车工业和钢铁工业等行业。目前，钨资源短缺，钨合金价格高、用量大，因此各国都把废弃的钨合金作为宝贵的第二钨资源加以再生利用。本文综述了钨合金的再生利用现状，分别总结了硬质合金、高比重合金、钨铜合金和钨材的再生利用技术，并利用生态环境材料的观点。对每种再生利用技术作了简单的评价。     

钼、钨及其合金

对钼、钨及其合金的重要物理性能、室温力学性能,钼及钨的合金,钼合金的应用等方面的近期文献资料作了综合评述。     

Application of Work-of-sintering concepts in powder metals

One of the current challenges facing the particulate materials industry is developing simple, accurate models to predict sintered properties. Work-of-sintering concepts, where time-temperature integrals are used in such models, offer a solution to this problem. In this study, the master sintering curve concept is applied to several powder metal systems: 17 to 4PH stainless steel, 316L stainless steel, nickel, niobium, tungsten heavy alloys with two different compositions, and molybdenum. A detailed explanation of the construction of these curves is given, including methods used to calculate the apparent activation energy for sintering and to curve-fit experimental data to a sigmoid function describing the master sintering curve. Discussion of the results shows that the master sintering curve can be applied to powder metal systems, even those that use liquid phase during sintering.     

Activity of carbon in nickel-rich Ni-Mo and Ni-W alloys

Effects of molybdenum and tungsten on carbon activity in nickel have been experimentally determined at 1000, 1100, and 1200 °C. Seventeen nickel-molybdenum and thirteen nickel-tungsten binary alloys were carburized in a flow of purified methane and hydrogen mixed gas. A sealed capsule technique was also employed for carburization of a few series of nickel-molybdenum alloys. The carbon concentration was determined either by hot extraction techniques (LECO and Coulomatic) or by weight gains of these specimens. The carbon concentration at a constant carbon activity decreases with increasing either molybdenum or tungsten concentration in nickel. The effect of tungsten on the carbon solubility in nickel is slightly larger than that of molybdenum. The experimental data were analyzed in terms of the regular solution model with two sublattices due to Hillert and Staffansson. Temperature dependence of the interaction coefficients between carbon and molybdenum or tungsten was expressed as DG_Mo/RT = −4.45 + 11650/T andDG _W /R = 1.21 + 9010/. Formerly Graduate Student, Department of Metallurgical Engineering, Tokyo Institute of Technology Formerly Professor, Department of Metallurgical Engineering, Tokyo Institute of Technology     

钨合金废料的资源再生利用技术

钨是一种稀有金属,钨合金具有高强度、高硬度、较好的耐高温性、耐磨性和良好的电性能,被广泛地应用于航空航天工业、兵器工业、核工业、信息产业、汽车工业和钢铁工业等行业。目前,钨资源短缺,钨合金价格高、用量大,因此各国都把废弃的钨合金作为宝贵的第二钨资源加以再生利用。作者综述了钨合金的再生利用现状,总结了硬质合金、高比重合金、钨铜合金和钨材的再生利用技术,并从生态环境材料的立场出发,对每种再生利用技术作了简要的评价。     

ICP-AES法测定稀土金属中的钛、钼、钨、铌和钽

针对试样特点拟定了加大称样量以减轻偏析,以浓硝酸溶解样品破坏碳化物,加入氢氟酸助溶,分离稀土基体同时络合钛、钼、钨、铌和钽的方法,无须基底匹配,采用工作曲线法成功地测定了金属镧、铈、镨、钕、钐、铕、钆、铽、镝、钇中的钛、钼、钨、铌和钽量,测定范围:0.0050%～0.50%。     

高纯钨、钼、钽、铌工业分析进展

评述了二十年来高纯稀有难熔金属领域钨、钼、钽、铌工业的分析进展,包括分光光度分析、原子吸收／发射光谱分析、质谱分析、中子活化分析和电化学分析等。引用文献50篇。通过对文献的多角度分析,反映了高纯钨、钼、钽、铌分析领域的行业布局,指出质谱分析等多元素同时痕量分析是高纯钨、钼、钽、铌工业分析的发展主流,但分光光度分析等单元素分析方法仍具有不可替代性。     

Effect of dissolved tungsten on the deformation of 70Ni-30Fe alloys

A series of Ni-Fe alloys containing various levels of tungsten in solid solution have been prepared as a means to assess the influence of solid solution strengthening on the mechanical behavior of monolithic 70Ni-30Fe. In particular, 70Ni-30Fe alloys plus equilibrium concentrations of tungsten in solid solution nominally correspond to the compositions associated with the matrix-only portion of certain tungsten heavy alloys, that is, alloys comprised of a high volume fraction of nominally pure tungsten particles embedded within a minority Ni-Fe-W based matrix. The study shows that the working solubility of tungsten within the 70Ni-30Fe base composition increases slightly with temperature, from approximately 21 wt pct at room temperature to approximately 23 wt pct at 1400 °C. Increasing the level of tungsten in solid solution leads to increases in room-temperature yield strength, tensile strength, and ductility. In contrast, the deformation characteristics of the alloys, as quantified by the power-law work-hardening exponent, n, and the strain-rate-sensitivity exponent, m, show little variation with tungsten solute concentration.     

Solid solution strengthening in Nb-Ta and Nb-Mo alloy single crystals

The strength of Nb, Nb-Ta, and Nb-Mo alloys was investigated in tension and compression as a function of composition, temperature, and strain rate. The room-temperature properties show molybdenum to have a significant effect on the strength of niobium while the effects of tantalum are nearly zero. The room-temperature strength is shown to be well correlated with the atomic misfit parameter. Analysis of the low-temperature behavior of Nb-Ta alloys indicates that they behave similarly to the pure metal while Nb-Mo alloys show a marked deviation from this behavior. The strengthening phenomena occurring in the Nb-Mo alloys at low temperature is interpreted as being an impurity interaction. A transition between the mechanism operating in the pure metal and the impurity interaction occurs at low solute contents. Formerly Graduate Student, Michigan Technological University, Houghton, Mich.     

2002年钼业年评

评述了2002年世界钼的供给、需求和价格，特别是综述了钼新产品、新技术，诸如黑色合金、有色合金、催化剂、润滑剂、缓蚀剂和阻燃抑烟剂等的研究与开发进展。     

2003年钼业年评

评述了2003年世界钼的供给、消费和价格，特别是综述了钼新产品、新技术，如冶金、黑色合金、有色合金、催化剂、润滑剂、缓蚀剂和阻燃抑烟剂等的研究与开发进展。     

以柠檬酸和过氧化氢为络合剂电感耦合等离子体原子发射光谱法测定选矿样品中钨和钼

以盐酸、硝酸、氢氟酸、硫酸、柠檬酸和过氧化氢溶解样品,选择W239.709 nm和Mo 284.823 nm的谱线分别作为钨和钼的分析线,用ICP-AES光谱法测定了样品中钨和钼含量。利用柠檬酸和过氧化氢与钨酸、钼酸络合作用,抑制钨酸和钼酸的析出,促使样品的快速溶解,确保了钨、钼测定结果的准确性。钨和钼的检出限分别为0.015 μg/mL 和0.003 μg/mL,测定下限分别为0.075 μg/mL和 0.015 μg/mL。当钨、钼含量分别在0.1~100 μg/mL范围内,其校准曲线均呈线性关系,且线性相关系数都在0.999 5以上。采用本方法测定钼矿石标准样品和选矿流程样品中钨、钼时,测定值与认定值或硫氰酸盐光度法或重量法的测定值相符。用钨矿石标准样品和选矿流程样品进行加标回收试验,测得钨的加标回收率在96%～105%之间,钼的加标回收率在94%～102%之间。     

2004年钼业年评

评述了2004年世界钼的供给、消费和价格，特别是叙述了钼的新产品、新技术，如矿冶、黑色合金、有色合金、超级合金、钼粉、催化剂、润滑剂、缓蚀剂、阻燃抑烟剂和抗菌剂等的研究与开发进展。     

Sintering of Tungsten and Tungsten Heavy Alloys of W–Ni–Fe and W–Ni–Cu: A Review

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.     

High-temperature electrometallurgical synthesis of tungsten and molybdenum carbides

Compositions of the products of the electrolysis of melts based on a eutectic mixture of sodium chloride-lithium fluoride and sodium tungstate, which contains molybdenum(VI) and tungsten(VI) oxides, molybdates, tungstates, and carbonates of lithium or sodium, are investigated. It is shown that, depending on the content of melt components, the products of electrolysis are carbon, molybdenum, tungsten, and their bronzes and carbides. The conditions of the deposition of galvanic coatings of molybdenum and tungsten carbides on carbon, nickel, and copper matrices are determined.     

Extraction of tungsten and molybdenum from grinding sludge of high-speed tool steels

Conclusions Investigations were carried out into the process of oxidizing roasting the sludge waste of R6M5 high-speed tool steel to extract, from the sludge, tungsten and molybdenum by sublimating and condensing the oxides.The developed phenomenological and mathematical models of the process were used to determine the technological parameters of combined sublimation of the oxides of tungsten and molybdenum. The degree of extraction of tungsten and molybdenum from the sludge of R6M5 steel was respectively 85 and 98%.The chemical and phase composition of the sublimates and products of reduction by hydrogen was determined. The total content of the impurities vanadium, chrome, and iron does not exceed 0.3%.The calculated production cost of the tungsten-nickel powder is 4000 rubles/ton.Translated from Poroshkovaya Metallurgiya, No. 2(302), pp. 68–72, February, 1988.