The oxidation of two ternary Ni-Cu-10 at.% Al alloys in 1 atm of pure O2 at 800-900 °C

The oxidation of the ternary alloys Ni-45Cu-10Al and Ni-30Cu-10Al has been studied at 800-900 °C under 1 atm O₂. The presence of 10 at.% Al reduces significantly the oxidation rate of the corresponding Cu-Ni alloys during the initial oxidation stages, even before the establishment of a complete Al₂O₃ layer. The weight of individual sample of the two ternary Ni-Cu-10Al alloys at 800 °C increases more rapidly than at 900 °C during the initial oxidation stage. As oxidation proceeds, the weight gain at 800 °C slows down to a degree that the total weight gain after 24 h oxidation at 800 °C is less than that at 900 °C. Due to a faster formation of the Al₂O₃ layer, which suppresses earlier the further oxidation of Cu and Ni, the external region of the scales grown on Ni-45Cu-10Al contain much less Cu and Ni oxides than those grown on Ni-30Cu-10Al. The transition from the internal oxidation to the selective external oxidation of the most reactive component Al in Ni-Cu-Al alloys is favored by higher values of the Al content, of temperature and of the Cu/Ni ratio.     

Cast bulk ZrTiAlCuNi amorphous alloys

Cylindrical bulk amorphous samples with diameters up to 10 mm have been prepared by casting ZrTiAlCuNi alloys in a copper mould. In order to rank glass-forming ability as a function of alloy composition, alloys were also cast into wedge-shaped moulds; to a first approximation, the thickness of the amorphous region obtained can be taken as an indication of glass-forming ability. The compositions which lead to the production of bulk glasses all have reduced glass transition temperatures in excess of 0.65 and the extremely high glass-forming ability of these compositions is discussed. We suggest that both the Al and Ti contents are determining factors for the production of bulk amorphous samples and these are believed to reduce the driving force for, and hence the rate of, crystallisation. These amorphous alloys have been found to display high thermal stability and can be annealed for several minutes in the supercooled liquid region. They are ductile at room temperature and have a high value of yield stress.     

中高频小功率电子元器件用非晶材料的开发与应用

随着电力和电子技术的飞速发展，相应的元器件向高频化，小型化，高效率和节能的方向发展，从而对元器件用材料也提出了更高要求。为此，本文概述了冶金部钢铁研究总院近年来所研究的用于开关电源，脉冲变压器，传感器，电流互感器和电感器等方面的非晶软磁合金的性能及其应用概况。     

Microstructure and creep of eutectic indium/tin on copper and nickel substrates

The behavior during creep in shear of eutectic indium-tin joints on copper and nickel substrates was examined in order to determine the effect of creep deformation on the microstructure of the alloy. Primary creep was absent in all the samples tested. The stress exponent at 20° C was much higher for samples on nickel than for those on copper, indicating a different creep deformation mechanism. Also, the microstructure within the indium-tin joints differed significantly with a change of substrate. Samples with a nickel substrate showed a colony microstructure that was not observed in those with a copper substrate. Thus, eutectic morphology is important in determining deformation mechanism during creep. The microstructure within the joints in tested and untested regions of the samples was effectively the same. This is quite distinct from the behavior of eutectic lead-tin observed in previous work. Lead-tin formed a recrystallized band of material along a region of concentrated shear deformation. While the deformation pattern in the indium-tin samples appeared to be the same as for lead-tin, the microstructural changes did not occur. This implies that the behavior observed in lead-tin is not universal to eutectic alloys.     

Drying of Prone to Twist Boards in a Pre-Twisted Position

A method to minimize twist has been investigated; i.e., drying the boards in a pre-twisted position. It has been found that Norway spruce boards can be deformed toward straightness by this method. The force exerted by a board on its holders during drying in a pre-twisted position has been measured. When the variation in torsional stiffness as a function of temperature and moisture content is accounted for, it is found that a creep deformation of the board occurs both during the drying phase and the cooling phase. In addition to mechano-sorptive creep, a deformation released by a change in temperature also seems to occur.     

不连续增强镁基复合材料的界面行为

综述了近年来国内外关于Ａｌ２Ｏ３短纤维、ＳｉＣ晶须、ＳｉＣ颗粒、Ｂ４Ｃ颗粒增强镁基复合材料的界面结构及其对复合材料性能影响的研究进展，并对今后的研究提出了一些看法。     

介绍一种生产冲挤用铝合金坯料的新工艺

哈兹列特铝板带连铸连轧工艺已被成功地用于铝和铝合金冲击挤压用坯料的生产。在对哈氏四个有关用户扫描的基础上，列举了其产品及其用途，并介绍了相关工艺及其优点。     

Effect of Microstructure on the Accelerated Creep of 20CrMoV12‐1 and P 91 Steels

In the initial part the change of microstructure for steel X20 CrMoV 121 is discussed in terms of the distribution of carbide precipitates and its effects on accelerated creep resistance and hardness are presented. In the following, experimental results of microstructure and accelerated creep resistance are presented for the steels X20CrMoV 121 and P91 annealed for up to 8760 hours at 650°C and 750°C before the testing. A similar evolution of the distribution of carbide particles of a size above 102 nm is found for both steels, while the accelerated creep resistance is diminished much stronger for the steel X20CrMoV 121. This difference is due to a greater stability of NbC than that of VC precipitates, both related to the evolution of the chemical composition of complex chromium, molybdenum and iron carbide particles.     

The distribution of nutrient elements in cell wall and other fractions of the herbage of some grasses and legumes

The distribution of 10 nutrient elements was assessed in three fractions of herbage samples of perennial ryegrass, tall fescue, white clover and lucerne. The cell wall fraction, prepared by mechanical disintegration of undried material, contained the following proportions of the total herbage content of the major elements: N, 2.9–16.4%; P, 3.0–6.9%; S, 3.6–17.2%; Ca, 11.3–51.8%; Mg. 6.4–27.6% and K, 0.1–1.7%. Substantial though more variable proportions of the trace element cations, Fe, Mn, Zn and Cu were also present in the cell wall fraction. The extent to which the elements were soluble in water was assessed by analysis of the water-insoluble fraction prepared from freeze-dried samples of each herbage. The proportions of the total herbage content of the major elements soluble in water were: N, 30–57%; P, 80–92%; S, 35–71%; Ca, 48–69%; Mg. 65–83% and K, 90–96%. With the trace element cations the proportions soluble in water were more variable, though they were generally less than 70% of the total. The extent to which the various elements were soluble in 80% aqueous ethanol was assessed by analysis of the insoluble fraction prepared from freeze-dried materials. With each of the major elements, smaller proportions of the total herbage content were soluble in 80% ethanol than in water, which may reflect in part the lower solubility of proteins and pectin. With the trace element cations, the differences in solubility between 80% ethanol and water were generally small and inconsistent.     

The magnetic applications choice among ferrite ceramics,metallic strips,or metal powder cores

Iron-based metallic strip materials such as iron, silicon-iron, and amorphous metal are used for low frequency (50–60 Hz. line) power applications. Low-loss Nickel-based alloys as high permeability strip or insulated powder cores are the choices for stable, low-level higher frequency applications. Iron-based powder cores offer low cost as power supply filter chokes. Ceramic ferrites combine highest frequency operation with low cost and reduced component size as transformers and chokes in telecommunication and high frequency power supply applications.