抗震钨丝的现状与展望

叙述了抗震钨丝的掺杂机理和制备工艺，指出只有掺入K、Si和Al，才能获得良好的抗震性能。文章还介绍了国内外生产现状，并对抗震钨丝的发展方向提出了新的见解。     

原位生成陶瓷相增强铝基复合材料物相组成和反应机制的研究

通过外加颗粒SiO2 采用粉末冶金法成功制备了原位生成陶瓷相增强Al基复合材料 ,定量研究了复合材料的物相组成和反应机制。主要反应方程式为颗粒内Al 1/ 2Mg SiO2 =1/ 2MgAl2 O4 Si和颗粒外 2Mg Si=Mg2 Si。最终物相由约为 16.5 %～ 18.4%MgAl2 O4 ,3 %～ 5 %Si,11.7%Mg2 Si,及大于 0 .5 2 %MgO ,其余为Al组成 ,约 7%Al参加了反应 ,Mg和SiO2 基本消耗尽。反应是以SiO2 颗粒为核心进行的。这种反应及元素的扩散可以用“逐层反应机制”和“元素微观通道扩散机制”来描述。     

TiO2对低氟渣系电渣重熔Incoloy825合金中Al、Ti元素影响的热力学研究

为了研究低氟渣电渣重熔过程中电渣锭中元素的变化,以Incoloy825合金为研究对象,渣中添加不同含量的TiO₂和脱氧剂,进行了四组电渣重熔试验;并基于离子分子共存理论、热力学理论和质量守恒定律建立Al、Ti含量控制的热力学模型。结果表明,随着渣中TiO₂含量的增加,电渣锭中Ti含量增加,Al含量减少,这是由于铝钛的交换反应4Al+₃TiO₂=3Ti+2Al₂O₃控制的,Si和Mn元素含量变化不大。当TiO₂含量不变时,Al、Ti元素的含量沿着电渣锭高度的方向上有不同程度的增加,Si、Mn元素的含量则均有所下降。当熔渣中■为-3.16时,结合Al脱氧剂的添加,可以得到Al、Ti含量均匀性较好的产品,试验结果很好地验证了热力学模型的准确性。     

等离子表面Cr-Si合金化改善TiAl基合金高温抗氧化性能的研究

利用等离子表面合金化技术,在TiAl基合金表面实现了Cr-Si二元共渗。通过SEM、EDS、XRD检测合金渗层的形貌、合金元素含量与相结构,并研究了合金化处理对TiAl基合金高温抗氧化性能的改善效果。结果表明,合金渗层组成相为Cr3Si及Laves相TiCr2,过渡层物相主要为Al8Cr5与Al3Ti,合金层内Cr、Si元素含量呈梯度分布;经高温氧化后合金渗层表层形成致密CrO2,内层形成连续Al2O3阻隔层,其氧化动力学曲线呈典型的抛物线型。     

12Mn钢连铸圆坯的原位统计分布分析

为获得连铸圆坯横截面内各元素的偏析、疏松和夹杂物分布,采用金属原位分析仪对12Mn无缝钢管连铸圆坯进行了原位成分统计分布分析。通过C、Si、Mn、P的二维成分分布图及线分布图看出,在中心部位处C元素呈明显富集状态,而Si、Mn和P则相反,即含量极低。在整个横截面内,C、Si、P等元素尤其是C元素含量表现为明显偏析状态,Al元素则由于夹杂物的形成而表现为分散的岛状富集分布状态,S则无明显变化,Si、Mn的分布极为相似。此外,通过定量分析和夹杂物粒度分析获得了各元素的含量频次图及Al粒度分布图。通过表观致密度分布图可以获得,圆坯横截面整体表观致密度低至95.60%,这是铸坯中心缩孔导致。     

2种含铝TRIP钢连续冷却转变动力学分析

用热膨胀法,通过对含1.5%w（Al）和含w（Al）1.0%＋w（Si）0.5%的2种TRIP钢的显微组织观察,绘制了2种不同w（Al）、w（Si）的TRIP钢的静态CCT曲线,研究了含Al TRIP钢在冷却过程中的相转变,分析了冷却速率及不同w（Al）对微观组织和贝氏体转变动力学的影响。结果表明,Al元素加速TRIP钢冷却时铁素体转变和贝氏体转变,但是推迟珠光体转变。     

Al-Fe-Si合金基体及强化相Al12(Fe,X)3Si价电子结构分析

基于EET理论,计算了Al-Fe-Si合金基体与强化相Al12Fe3Si,Al12(Fe,X)3Si的价电子结构,探讨了价电子结构与合金强化、合金相稳定性的关系及合金元素X对强化相稳定性的影响.结果表明:与基体α-Al相比,强化相Al12Fe3Si,Al12(Fe,X)3Si的n(A)值分别增强了248%,208%～231%,位错运动阻力分别增大2.48倍和2.08～2.31倍,从合金相价电子结构参数n(A)看,溶质原子固溶强化作用弱于析出相的强化作用;合金元素V,Cr,W,Mo,Mn的加入改变了Al12FeSi的价电子结构,使其原子状态组数σ(N)增加了2个数量级,使合金相的稳定性增强,进而延缓了粗化速度;V,Cr,W,Mo,Mn对Al12Fe3Si相稳定性影响的强弱顺序为Cr(Mn)→W(Mo)→V.     

Nb、Al协同合金化MoSi_2材料的燃烧合成与组织结构

以Mo、Nb、Si、Al元素粉末为原料,采用燃烧合成法制备名义成分分别为(Mo0.97Nb0.03)(Si0.97Al0.03)2、(Mo0.94Nb0.06)(Si0.97Al0.03)2、(Mo0.91Nb0.09)(Si0.97Al0.03)2与(Mo0.88Nb0.12)(Si0.97Al0.03)2等4种不同化含量的合金,研究其燃烧合成行为,分析燃烧合成过程中粉末压坯的燃烧模式、燃烧温度、燃烧波前沿蔓延速率以及产物组成。结果表明:随Nb含量增加,燃烧合成反应模式由螺旋燃烧逐渐转变为稳态燃烧。添加Nb、Al后,合金的最高燃烧温度升高,并随Nb含量增加呈现先升高后降低的变化趋势,其中(Mo0.91Nb0.09)(Si0.97Al0.03)2的燃烧温度最高,达到1 924 K,但燃烧波蔓延速率随Nb含量增加而逐渐降低。XRD结果表明:(Mo0.97Nb0.03)(Si0.97Al0.03)2合金主要由MoSi2构成,含有少量Mo(SiAl)2和Mo5Si3;(Mo0.94Nb0.06)(Si0.97Al0.03)2中开始出现NbSi2相,(Mo0.91Nb0.09)(Si0.97Al0.03)2和(Mo0.88Nb0.12)(Si0.97Al0.03)2合金中Mo5Si3的衍射峰强度进一步降低,而NbSi2的衍射峰略有增强,因而添加Nb有利于形成C40结构的NbSi2,同时抑制Mo5Si3的产生。SEM观察表明合金为多孔结构。     

偏振能量色散X-射线荧光光谱法测定水系沉积物和土壤样品中多种组分

采用粉末样品压片制样,用偏振能量色散X-射线荧光光谱仪对水系沉积物和土壤样品中多种元素进行测定。除Na,Si和Fe外,其余元素利用经验系数和二级靶的康普顿散射线作内标校正基体效应。分别采用了Al2O3,W,BaF2,CsI,Ag,Rb,Mo,Zr,SrF2,KBr,Ge,Fe,Ti和Al等不同偏振靶(或二级靶)对被分析元素进行选择激发和测定。在总测量时间为2 000 s(每个样品)的条件下,除Na,Mg,Al,Si,P,K等轻元素外,其余各元素的检出限达到0.25-14.80μg/g。     

料浆法制备NiCrW基高温合金Al-Si涂层的微观结构与性能

航空发动机涡轮叶片在使用时需加以涂层防护,以提高基体合金的抗高温氧化性能。本研究采用料浆渗铝的制备工艺,以CaCl₂作为活化剂,在NiCrW基高温合金表面制备Al-Si涂层。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)及能谱仪(EDS)对涂层试样的表面和截面进行分析。结果表明,聚乙烯醇水溶液可作为料浆法制备渗铝/铝硅涂层的有效黏结剂;高温扩散的温度和时间显著影响渗铝涂层的厚度。渗剂成分为5%Si+30%Al(质量分数),制备得到的共渗涂层由外而内依次为富Al层、NiAl层和含Si过渡层三部分,涂层致密无明显缺陷,厚度约为57μm。10%Si+25%Al、15%Si+20%Al与20%Si+15%Al共渗涂层由外而内分为富Al层、富Ni层和含Si过渡层三层。Si元素主要以含Si的沉积相形式存在于含Si过渡层中,少量沉积于外层。而Si的少量添加能明显影响Al、Ni元素的扩散过程,从而减小涂层厚度,并由单一NiAl相向富Al、富Ni的镍铝相转变。     

Recrystallization of molybdenum wire doped with potassium-silicate

The doping effect of the bubble formation oxide on the recrystallization of Mo wire was investigated. Five different wires of 1 mm in diameter were prepared through sintering, swaging, and drawing processes. Each wire was doped with various amounts of potassium (K) plus silicon (Si), i.e., 0, 0.028, 0.14, 0.28, and 0.49 by weight percent, and annealed for 30 minutes at given temperatures. To understand the overall recrystallization phenomena, changes in hardness and in optical microstructures were examined. Transmission electron micrographs were taken for the specimens in the as-drawn state and at the beginning of the decrease in hardness. And also, the relative excess resistivity was measured as a function of heating temperature to confirm the occurrence of the abnormal grain growth. During the grain growth, bubble dispersion was evaluated through fractography by scanning electron microscopy (SEM). Primary re-crystallization started at 750 °C regardless of the amount of dopants. For the specimens doped with 0.14 and 0.28 (K + Si), large elongated and interwoven grain structures indicating ab-normal grain growth developed over 1400 °C and 1600 °C, respectively. For the specimens doped with 0.028 and 0.49 (K + Si), however, small equiaxial grain structure developed similar to pure molybdenum wire. Such a difference was understood through the relationship between grain structures and bubble dispersion parameters (the average bubble diameter, the bubble row density, the columnar bubble spacing, and the bubble row distance). It was concluded that two of the most important parameters to develop a grain structure of high aspect ratio were bubble row density and bubble row distance. At a high bubble row density, irregularity in bubble row distance induced the higher aspect ratio (length/width (L/W)) of grain.     

The effect of wire history on the coarsened substructure and secondary recrystallization of doped tungsten

This article reports a study of primary and secondary recrystallization in tungsten wire. Samples with two different processing histories were annealed in the electron emission microscope, and the recrystallization process was followed. The fibers produced by drawing were first observed to widen and break up into shorter lengths. As the temperature was raised, the secondary recrystallization occurred in a characteristic, stepwise motion, with the secondary grain moving from one position to the next and then remaining pinned at the new position, sometimes for the entire length of the test. It was found that the temperature at which secondary recrystallization occurred depended on the heating rate. If a slow heating rate was used, the temperature at which secondary recrystallization occurred would be higher. This result was interpreted to mean that the slower heating rate allowed more strain to be annealed out of the wire before secondary recrystallization occurred and thus lowered the driving force for this process. The secondary recrystallization temperature could not be correlated with the primary grain structure or differences in the potassium bubble distribution in the wire. The primary recrystallized grain structures of the two wires were also different, and this difference, too, was attributed to differences in the amount of stored energy in the wire at the start of the annealing. It was also shown that even though the bulk potassium content of the two wires was the same and the bubble distributions in the two wires were similar, the bubble distributions in the ingots were different.     

铜包铝丝材的旋锻复合-拉拔成形与组织性能

采用"热旋锻-拉拔"方法制备了直径为φ65 μm、包覆铜层厚度较均匀、表面质量高和界面结合质量良好的铜包铝复合微丝,研究了合理热旋制度、热旋复合成形铜包铝线材的组织和界面结合状态以及中间退火和拉拔对线材组织与性能的影响.结果表明:合理的旋锻制度为旋锻温度350℃,单道次变形量40%,旋锻后形成了动态再结晶组织和厚度为0.7 μm的界面扩散层.复合线材的合理退火工艺参数为350℃/30 min (退火温度350℃、退火时间30 min),该条件下退火后线材延伸率达到最高值35.7%,界面扩散层厚度约为2.1 μm,退火后铜层和铝芯发生再结晶,组织内部形成等轴晶组织.当退火温度超过350℃时,铜层和铝芯晶粒长大,界面扩散层厚度增加,从而导致线材的延伸率下降.将单道次变形量控制在15%~20%,经过粗拉,制备了φ0.96 mm的丝材;粗拉后不进行退火处理,将单道次变形量控制在8%~15%,经过细拉,制备了表面光洁、直径为φ65 μm的复合微丝.在拉拔过程中,铜层和铝芯均出现〈111〉丝织构.      

Dopant particle characterization and bubble evolution in aluminum-potassium-silicon-doped molybdenum wire

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.     

The recrystallization of commercially pure and doped tungsten wire drawn to high strain

The recrystallization processes in both undoped and doped tungsten wire after drawing to a true strain of 7.7 were examined by light microscopy and transmission electron microscopy. High angle grain boundary migration commenced at approximately the same temperature in both materials, but proceeded much more rapidly in the undoped wire, where the absence of a potassium bubble dispersion allowed a coarser, more equiaxed grain structure to form. No change from the (110) deformation texture was observed in either case. Recrystallization in the undoped wire was dominated at lower temperatures (1100 to 1200°C) by the growth of large grains into a much finer structure. As the annealing temperature was increased, this process was replaced by a general grain coarsening which eventually produced a relatively equiaxed recrystallized grain structure. It appeared probable that it was the second phase dispersion inhibition alone that prevented similar structural changes in the doped wire. This paper is based on a presentation made at a symposium on “Recovery Recrystallization and Grain Growth in Materials” held at the Chicago meeting of The Metallurgical Society of AIME, October 1977, under the sponsorship of the Physical Metallurgy Committee.     

Observations on the evolution of potassium bubbles in tungsten ingots during sintering

The present article describes the evolution of potassium bubbles during sintering of tungsten ingots pressed from doped powder. In the manufacture of incandescent lamp filaments, tungsten powder is produced by reduction of blue tungstic oxide which is doped with potassium disilicate and aluminum chloride. The reduced tungsten particles contain submicron pores. Analytical transmission electron microscopy (TEM) identifed two types of pores in reduced tungsten powder. First, there are pores which contain particles which consist of potassium, aluminum, and silicon, and second, there are pores which contain aluminum and silicon alone. On sintering at 2100 °C or 2300 °C, potassium aluminosilicate particles migrate together with grain boundaries to necks which form between tungsten particles. Sintering at 2100 °C or 2300 °C reduces the potassium, aluminum, and silicon concentrations of the particles. Atomic absorption spectroscopy (AAS) also measured reductions in the bulk potassium, aluminum, and silicon concentrations. In the present study, analytical TEM and Auger electron spectroscopy (AES) were used to describe the decomposition of dopant particles and the evolution of elemental potassium bubbles in sintered ingots.     

Image analysis for grain shape characterization in lamp filaments

Algorithms have been developed for appraising the quality of tungsten lamp filament wire microstructure with respect to its resistance to sag. They allow a numerical determination of grain aspect ratio, grain boundary contour, angle of boundary with wire diameter, and degree of grain boundary surface convolution. These values are combined algebraically to give a grain shape parameter (GSP) which reliably predicts how resistant the filament is to grain boundary sliding. Measurements are made of thermally etched grain boundaries on scanning electron microscopy (SEM) images of the surfaces on coiled filaments. Data are recorded and parameters computed by means of an image analyzer. The technique has been tested on samples made from the same wire modified in process to have varying strain after the last anneal. It has also been tested on samples purchased from various vendors. These applications indicate that the computed GSP is a sensitive predictor of filament creep resistance and reliably reflects variation in wire drawing strain after the last anneal.     

500kV铝包钢丝绞线良导体地线的研制

针对应用于目前最高电压等级线路500kV线路良导体的铝包钢绞线需要解决的大长度、高耐温、高延伸、高强度、高导电率、高结合力问题及钢芯拉拔、绞线的合理结构和绞制等几个重大的技术难题进行了分析研究。     

ICP-AES技术对钼酸铵产品中钨、硅和铝的测定

采用由感耦合等离子体原子发射光谱分析技术 (ICP -AES)对钼酸铵产品中的钨、铝和硅的最佳测试条件的选择进行了探讨 ,并用所选的条件进行测试。方法简便、快速、准确 ,检测限和精密度可满足分析要求     

Microstructural influences on the

The influence of tungsten content, swaging, and grain size on the dynamic behavior of commercially available tungsten-nickel-iron (W-Ni-Fe) alloys has been examined using the compression Kolsky bar. The observed flow stresses increase with increasing tungsten content and with degree of swaging but are essentially independent of grain size for these compressive deformations. Further, the flow stresses sustained by these materials have a distinct dependence on strain rate, in that the flow stress increases by at least 20 pct over a range from 10^-4 s^-1 to 7 × 10³ s^-1. The rate sensitivity itself increases with increasing tungsten content. The rate sensitivity of the alloy with the highest tungsten content (97 pct W) appears to be essentially the same as that of pure polycrystalline tungsten. In addition to showing greater strain hardening, the unswaged alloy also shows a much higher rate dependence than the swaged alloys, with the flow stress almost doubling when the rate of deformation increases from quasistatic to 5 X 10³ s^-1. The rate-hardening mechanism within the composite appears to be essentially that as- sociated with the tungsten grains; however, the matrix contribution is significant in the case of an unswaged alloy. Formerly with The Johns Hopkins