巻号一覧
69 巻, 4 号
選択された号の論文の13件中1～13を表示しています
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飯島 嘉明, 新田 広行, 仲村 龍介, 高澤 孝一, 井上 明子, 竹本 繁, 山崎 仁丈2005 年 69 巻 4 号 p. 321-331
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーExperimental techniques for precise determination of low tracer diffusion coefficients in solid metals and alloys using radioisotopes are reviewed. Sputter-microsectioning method is most useful to measure submicron diffusion profiles at low temperatures. Measurements of tracer diffusivity along grain boundaries and dislocations in iron and stainless steels from the analysis of type C kinetics as well as type B kinetics are discussed.
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宮村 会実佳, 志摩 真也, 小原 共平, 須佐 匡裕2005 年 69 巻 4 号 p. 332-340
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーThe non-stationary, hot-wire method has been developed for use with an insulated, coated probe in order to determine thermal conductivities of metals. This development was carried out using both simulation and experimentation. The simulations of the temperature increase (ΔT) of the heater were carried out using various solid samples (Al, V, Ag and W). Experiments were carried out using hot-strip and hot-wire probes to determine ΔT from the voltage change (ΔV) using the four terminal method. Measurements of ΔT on solid Fe, Ni and Ti were made using hot-strip probes with coatings of (i) silica (ca. 5 μm thickness) and (ii) mica (20-300 μm thickness). Similarly, experiments were carried out on liquid Hg and Ga using hot-wire probes with coatings of (i) silica (ca. 5 μm thickness) and (ii) alumina-based material (170-470 μm thickness). The results of simulations and experiments have shown:
(1) The following equation applies to dΔV/d ln t (t: time) obtained using an identical probe:
dΔV/d ln t=A (I3•αT•R273•XT/4π)•(1/λ)+B
where dΔV/d ln t is an average slope for the time period 1-2 s, λ is the thermal conductivity at a certain temperature (T), I is the current supplied to the heater, αT is the temperature coefficient of electric resistivity of the heater at T K, R273 is the resistance between the potential leads for the four terminal method of the heater at 273 K, XT is the resistance per unit length of the heater at T K, and A and B are probe constants.
(2) The probe constants are independent of temperature. Thus equations for other temperatures (T1) can be obtained by replacing temperature-dependent terms αT and XT in the above equation by those for T1 as follows:
dΔV/d ln t=A(I3•αT1•R273•XT1/4π)•(1/λ)+B
Using these relations, the thermal conductivity of liquid Ga was determined over the temperature range (310-500 K). It has also been found that determination of the thermal conductivity is unaffected by coating thickness providing that the thickness of the insulating layer is <ca. 300 μm.
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井上 忠信, 曹 財榮, 殷 福星, 長井 寿2005 年 69 巻 4 号 p. 341-347
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーElectron backscattered diffraction analysis has been used to investigate the effect of shear deformation on the microstructural evolution of a Ni-30Fe alloy during hot deformation. The alloy was compressed by 50% or 75% in thickness at a strain rate of 1/s in a single pass at 1023 K using a hot compression simulator. An explicit finite element analysis was carried out to evaluate the inhomogeneous strain distribution introduced in the specimens by hot compression simulator. As the equivalent strain increased, the fraction of high angle grain boundaries with misorientaions between 15° and 30° increased almost in the similar way regardless of the presence of shear strain. The fraction of high angle grain boundaries having misorientations in excess of 30° increased mainly at the expense of low angle grain boundaries with misorientations smaller than 15°. Such the expense occurred at much higher rate with shear strain than without shear strain. The compressive direction changed continuously in the areas with shear strain component during deformation, which was thought to accelerate the subdivision of austenite grain interiors with increased misorientations between subdivided local areas.
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高木 秀有, 道 明, 藤原 雅美, 大塚 正久2005 年 69 巻 4 号 p. 348-355
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーIndentation creep tests of an Al-5.3 mol% Mg solid-solution alloy were performed using a microindenter in order to examine whether creep properties can be extracted accurately from a testpiece which is as small as a rice grain. A conical indenter was pressed into a surface with a load of 0.39 N at temperatures ranging from 546 to 590 K. When the average equivalent stress σm in the region beneath the indenter decreases to a critical stress σc during the creep indentation, the creep stress exponent n changes from 4.9 to 3.0. The measured σc-value decreases from 122 to 52 MPa with increasing temperature, while the corresponding indentation strain rate εc increases from 1.22×10-3 to 2.00×10-3 s-1. The temperature dependence of σc and εc is almost in agreement with the results derived from dislocation theory. The activation energy Q for creep in the stress range H (σm>σc) is approximately equivalent to that for the lattice diffusion of pure aluminum, 144 kJ mol-1. The Q-value in the stress range M (σm<σc) is close to the activation energy for the mutual diffusion of this alloy, 130 kJ mol-1. With load-jump tests at T=573 K, indentation load was abruptly changed from 0.39 N to various values ranging 0.19-0.59 N. In the stress range H, instantaneous plastic deformation (IPD) takes place evidently even when the load increment ΔF is very small. In the stress range M, the IPD does not occur when ΔF is within a certain value. However, the occurrence of IPD is observed when σm coincided with σc. The findings suggest that the creep rate-controlling process changes from recovery control (n=4.9) to glide control (n=3.0) below σc. These results agree well with those of conventional uniaxial creep tests. Consequently, the indentation testing technique can be used effectively to extract creep parameters from small-volume samples.
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森田 孝治, 平賀 啓二郎, 金 炳男, 目 義雄2005 年 69 巻 4 号 p. 356-361
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーThe effect of second phase dispersion on high-strain-rate superplasticity was examined in tetragonal ZrO2 dispersed with 30 vol%MgAl2O4 spinel. The spinel particle enhances the diffusivity of ZrO2 by supplying small amounts of aluminum and magnesium into ZrO2 and suppresses grain growth by grain boundary pinning. After superplastic flow, the spinel particles highly elongate along the tensile direction. In the spinel particles, intragranular dislocations were observed, indicating that the spinel particles may contribute to the relaxation of stress concentrations around grain junctions exerted by grain boundary sliding. Comparison with earlier studies suggests that the dispersion of spinel particles can attain high-strain-rate superplasticity in tetragonal ZrO2 through providing the following positive factors simultaneously; (i) the suppressed grain growth, enhanced accommodation process due to the accelerated (ii) diffusivity and (iii) stress relaxation.
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堀田 英樹, 久慈 俊郎, 内田 裕久2005 年 69 巻 4 号 p. 362-367
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーThe thermodynamic properties of palladium and palladium based fcc alloys-hydrogen systems have been extensively studied. It is well known that there is a good correlation between hydride stability and cell volume for palladium based fcc alloys. In this research, the dominant factor for the hydride stability was discussed in terms of the conventional thermodynamics. Calculated chemical potential of hydrogen was analytically separated into the infinite dilute solution of hydrogen and the excess chemical potential of hydrogen.
There was a sufficiently good correlation between the chemical potential of infinite dilute solution of hydrogen and the hydride stability of palladium based fcc alloys. On the other hand, the correlation was poor between the excess chemical potential of hydrogen and the hydride stability. These results led to the conclusion that the plateau pressure of palladium based fcc alloys was dominantly controlled by the chemical potential of infinite dilute solution of hydrogen.
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Xin Jiang Hao, 大塚 秀幸, 和田 仁2005 年 69 巻 4 号 p. 368-372
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーStructural elongation and alignment in an Fe-0.4C alloy isothermally transformed in high magnetic fields has been studied by quantitative microscopy analysis. It has been already reported by the authors that an elongated and aligned structure is obtained during continuous cooling as far as some conditions are satisfied. It is shown in this paper that an elongated and aligned two-phase structure is formed in high magnetic fields by isothermal ferrite transformation both below and above Curie temperature. To clarify if the elongated structure is formed in the nucleation stage or growth stage, transformation behavior in magnetic fields has been investigated and it was found that equiaxed ferrite grains nucleate randomly at austenite grain boundaries and they become elongated by preferred growth along the direction of applied magnetic field. Effects of isothermal transformation temperature on the degree of elongation has been studied. Below Curie temperature, the degree of elongation increases with increasing transformation temperature, whereas it decreases above Curie temperature. Small chemical driving force for ferrite precipitation and large magnetization of ferrite in high magnetic fields favor the formation of elongated structure.
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門脇 睦, 高橋 啓介, 松村 義人, 西 義武2005 年 69 巻 4 号 p. 373-376
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーSm-Fe alloy thin films were prepared by DC magnetron sputtering process. The atomic ratio of Sm-Fe film was varied from SmFe2.4 to SmFe2.0 with increasing Ar gas pressure from 0.2 to 1 Pa. A magnetostriction of the SmFe2.2 film increased with decreasing Ar gas pressure.
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門脇 睦, 増田 進吾, 松村 義人, 西 義武2005 年 69 巻 4 号 p. 377-379
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーInfluences of composition on magenetostriction of Sm-Fe alloy thin films prepared by D.C. magnetron sputtering process were investigated. Composition of formed film was ranged form 25 to 59 at%Sm. Negative magnetostriction were obtained of amorphous Sm-Fe thin films. The magenetostriction of thin films was varied with composition rate of Sm-Fe alloy. The giant magnetostriction over 1000 ppm at 400 kA/m was observed from 29 to 34 at% for Sm-Fe alloy film. The giant magnetostrictive (Sm-Fe) alloy thin film showed its potential use as wireless actuators in microsystem technology.
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岩田 圭祐, 利根川 昭, 西 義武2005 年 69 巻 4 号 p. 380-384
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーEffects of sheet electron beam irradiation on hardness, brittleness and fracture toughness of borosilicate glass were studied. The irradiation, which was one of short-time treatments at low temperature below boiling point of water, reduced the brittleness and enhanced fracture diameter, fracture load and fracture toughness of borosilicate glass surface. The fracture toughness enhancement can be explained by stress relaxation induced by increase in density of dangling bonds.
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万谷 義和, 竹元 嘉利, 飛田 守孝, 榊原 精, 田島 守2005 年 69 巻 4 号 p. 385-391
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーThe orthorhombic α" martensite was formed in Ti-8 mass%Mo alloy by quenching from 1223 K. The purpose of this study was to investigate phase transformation of the α" martensite structure by isothermal aging. In differential scanning calorimetry curve of the quenched specimen, an exothermic peak that indicated decomposition from the α" martensite to α and β phases was observed near 780 K, so that isothermal aging was performed at 723 K and 923 K for 9.0 ks. Optical microscopy, X-ray diffraction and transmission electron microscopy were performed to these specimens. Band-like products that were composed of the single variant of ω phase were observed in the quenched α" martensite structure. On the other hand, (111)α" twins were observed in the 723 K-aged α" martensite structure. The quenched α" martensite structure indicated low elastic incline and good ductility, whereas the 723 K-aged α" martensite structure indicated high yield stress and brittleness. It was pointed out that the ω products were formed to relax the volume expansion from the β phase to the α" martensite, and the (111)α" twins were formed during the isothermal aging at 723 K with the extinction of the ω products.
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杉山 陽栄, 小早川 久, 竹田 美和, 高嶋 圭史, 浪花 健一2005 年 69 巻 4 号 p. 392-398
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーWe report on characteristics of the photocathode using cesium telluride thin film for an electron gun in this paper. The quantum efficiency of a cesium telluride photocathode changes in accordance to deposition conditions of cesium telluride.
Conditions here include: the thickness of tellurium, the quantity of deposited cesium, passage of time from production of thin film, and a substrate condition to deposition. We show the results of measurement of a thickness dependence of the quantum efficiency. It is observed that the quantum efficiency has a peak at thickness of tellurium about 10 nm.
We conceived a model for a photoemission from cesium telluride thin film on metal substrate. This model can explain the results of this experiment qualitatively. This model has parameters of dependence on reflections of thin film and metal substrate, and dependence on thickness of thin film. It can explain that quantum efficiency has its peak under thickness of 10 nm, and it can estimate that unknown optical constants of cesium telluride.
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東雲 秀司, 永山 勝久2005 年 69 巻 4 号 p. 399-401
発行日: 2005年
公開日: 2005/10/12
ジャーナル フリーIt is reported that La-Al-Transition Metal alloys have high undercooled melt formation and high bulk amorphous formation ability by using rapid solidification process.
We have examined the undercooling solidification and remarkable nucleation control behavior with adding SiC whisker by using containerless process.
In this study, we investigated the undercooling, nucleation behavior and bulk amorphous formation for La55Al25Cu10Ni5Co5 samples and samples with SiC whisker addition which are levitated and solidified by using the new gas jet flow and high cooling type electromagnetic levitation system. Therefore, the nucleation was controlled and the high undercooling degree, ΔT(=0.22~0.28Tm), was obtained with increasing SiC whisker addition. In addition, the bulk amorphous sample, φ7 mm sphere, was obtained at the cooling rate of levitating melt and solidification, about 100 K/s, for sample with 0.2% or more SiC whisker addition.
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