巻号一覧
54 巻, 2 号
選択された号の論文の18件中1～18を表示しています
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近藤 慎一郎, 喜多 英治, 白鳥 紀一, 井野 博満1990 年 54 巻 2 号 p. 125-130
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーMelt-spun La100−xFex alloys (x=1, 4, 8) have been investigated by magnetization, X-ray diffraction and the Mössbauer effect. The lattice constant of the fcc β-La phase predominantly quenched is independent of iron content and the increment is less than 0.2% compared with that of pure La. A quadrupole doublet with a splitting of 0.44 mm/s is observed in the Mössbauer spectra measured at 300 K. The above results suggest that most of iron atoms are not solved in the fcc lattice but clustered each other. The inverse magnetic susceptibility 1/χ shows the formation of ferromagnetic clusters containing about 100 iron atoms in average.
Magnetization measurements show that ferromagnetic transition occurs at about 300 K and that there exists superparamagnetism between 300 and 400 K. We propose a model that the clusters interact each other and the ferromagnetic behaviour is attributed to the cluster-cluster interaction. Based on molecular field approximation, we conclude that experimental results can be explained as a system of the clusters with the average magnetic moment of 200 to 230 μB and the Curie temperature of 270 to 290 K.抄録全体を表示PDF形式でダウンロード (727K) -
柴柳 敏哉, 北詰 喜啓, 堀 茂徳1990 年 54 巻 2 号 p. 131-138
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThe relation between the grain boundary structure and discontinuous precipitation in Cu-2Be alloy has been investigated in connection with Co addition and aging temperature.
The solution treatments of Cu-2Be, Cu-2Be-0.15Co and -0.3Co alloys were performed at 1093 K for 160, 86.4 and 86.4 ks, respectively. The average grain size of Cu-2Be and Cu-2Be-0.15Co alloys was about 70 μm. Cu-2Be-0.3Co alloy had the average grain size of 40 μm. After aging at 573, 673, 773 and 823 K, the microstructure of specimens were observed with OM, SEM and TEM. The structure of a grain boundaries was characterized with the sigma value in the CLS theory which was determined by analyzing the ECPs (Electron Channeling Patterns) from two grains separated by the grain boundary.
Discontinuous precipitation was not observed at the twin boundaries of these alloys under any aging conditions. The number of grain boundaries without nodules was the least in specimens aged at 673 K. The width of nodules was small at the grain boundary of which the sigma values were smaller than 29 in Cu-2Be alloy aged at 773 K, while there was a weak correlation between the sigma values and the width of nodules in the specimens aged at 673 K. Thus, the influence of the grain boundary characters on the discontinuous precipitation depends on the aging conditions and the driving force for the discontinuous precipitation. The addition of Co retarded the progress of the precipitation without changing the number of grain boundaries without nodules. Meanwhile, the number of grain boundaries without nodules increased with increasing amount of Co.抄録全体を表示PDF形式でダウンロード (1647K) -
趙 丕植, 小坂井 孝生, 宮崎 亨1990 年 54 巻 2 号 p. 139-145
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーFree energy of the Fe-base ternary ordering alloys where B2 and DO3 ordered structures are formed is evaluated by a statistical approach employing the Bragg-Williams-Gorsky approximation: the magnetic interactions are taken into account between the first and the second nearest neighbour spins of atoms as well as the usual atomic interactions up to the second nearest neighbours. An application of this model was performed on the Fe-Si-V ternary ordering system. The equilibrium phase diagrams of the Fe-Si-V systems given by the present calculation are consistent with the previously obtained experimental results. It becomes also clear in the calculation that not only the two-phase field becomes much wider but also the driving force for the phase separation increases by considering the ferromagnetic interaction.抄録全体を表示PDF形式でダウンロード (805K) -
大木 千尋, 内田 裕久, 黄 燕清1990 年 54 巻 2 号 p. 146-152
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThe phase equilibria of the PrH2-H and NdH2-H Systems were investigated by measurements of the pressure-concentration-temperature curves using Sieverts’ type apparatus made of stainless steel. The measured P-C-T curves of these systems indicated plateaux in the H2 absorption and desorption processes. Large hysteresis phenomena were also observed in the measured curves. The appearance of the plateaux suggested the co-existence of their dihydride and trihydride phases in those regions. The crystal structures of PrH3 and NdH3 were also analyzed for the identification of the formation of trihydride phase for each system by using an X-ray diffraction measurement at room temperature in the air. The trihydride phases for Pr and Nd are having a h.c.p. structure. This result suggests that the present classification of the lanthanoide metal which does not form the LnH3 phase as the lighter and which does form the LnH3 phase as the heavier is having little significance.抄録全体を表示PDF形式でダウンロード (973K) -
増野 茂美, 堀谷 貴雄, 鈴木 洋夫, 岸 輝雄1990 年 54 巻 2 号 p. 153-160
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThree-dimensional location analysis and source characterization of acoustic emissions (AE) were conducted in the fracture toughness test to understand the microfracture process of Extra Low Interstitials (ELI) Ti-6Al-4V alloy with equiaxed α microstructure. Scanning Electron Microscope observation was also carried out for both fracture surfaces and microstructures near the notch tips of the unloaded specimens to supplement the AE analysis.
From about 50% of the maximum load in the fracture toughness test of ELI Ti-6Al-4V, many microvoids with diameters smaller than 10 μm began to nucleate near the crack tip and then microcracks of about 20 to 40 μm in diameter were generated by coalescence of these microvoids. These microcracks were located about 30 to 50 μm above or below the fatigue pre-crack plane. The stress relaxation near the crack tip due to the microcracks and zigzag type coalesence of microcracks was thought to enhance the fracture toughness of ELI Ti-6Al-4V alloys.抄録全体を表示PDF形式でダウンロード (1925K) -
鈴木 吉哉, 坂口 浩一, 中桐 俊男, 佐野 信雄1990 年 54 巻 2 号 p. 161-167
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThe purification of metallurgical grade silicon (MG-Si), especially the removal of phosphorus and boron, was investigated by applying the vacuum evaporation for phosphorus and plasma treatment for boron, respectively, to develop a new production technique of solar grade silicon (SOG-Si) at low cost.
The concentration of phosphorus in the MG-Si decreased from 32 mass ppm to 6 to 7 mass ppm after 3.6 ks by vacuum treatment at 0.027 Pa. The concentration of calcium and aluminum also decreased. It has been demonstrated that the overall evaporation of phosphorus and calcium is controlled by the diffusion of these elements through silicon melt to the gas-metal interface.
In the experiment of plasma treatment, the MG-Si was melted under various oxidizing plasma conditions by using Ar+O2 or Ar+CO2 as an operating gas for 30 to 1800 seconds. It has been found that the concentration of boron in MG-Si decreased from 28 mass ppm to 2 to 4 mass ppm and boron in MG-Si can be removed as a gaseous boron oxide. A mechanism of boron elimination under the oxidizing plasma conditions is discussed.抄録全体を表示PDF形式でダウンロード (1017K) -
鈴木 吉哉, 杉山 剛, 高野 清隆, 佐野 信雄1990 年 54 巻 2 号 p. 168-172
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThe thermodynamics of the removal of boron, which is most difficult among various impurity elements, was investigated by applying the flux treatment in order to develop a new production technique of solar grade silicon (SOG-Si) by refining inexpensive metallurgical grade silicon (MG-Si).
The equilibrium distributions of boron between silicon and various fluxes CaO-SiO2, CaO-CaF2-SiO2, CaO-MgO-SiO2 (-CaF2) and CaO-BaO-SiO2 (-CaF2) systems were determined from 1723 to 1823 K under CO or Ar atmospheres. The distribution of boron has a maximum with increasing basicity and increases with raising temperature for all fluxes studied.
The reaction of the removal of boron from silicon to flux is expressed as follows;
(This article is not displayable. Please see full text pdf.)
\ oindentFrom those findings, the mechanism of boron removal is discussed.抄録全体を表示PDF形式でダウンロード (708K) -
下尾 聰夫1990 年 54 巻 2 号 p. 173-180
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThe reduction rates of powdered FeCr2O4 and MgCr2O4 in a graphite crucible as reductant have been measured by means of thermo-balance under an argon atmosphere at temperatures from 1773 to 2073 K. Depending on particle size of oxide and temperature, there is the transition from one reaction mechanism to another as the reduction progresses.
The rates of reduction increase with increasing particle size, particularly in the early stage of reduction. The overall rate of reduction is controlled by gas dfffusion through the interparticle pores within the powder.
At lower temperatures, the reduction of fine particles is drastically retarded by the formation of densely sintered layers of oxide and the reduction product.
At higher temperatures, the reduction of FeCr2O4 is markedly accelerated as a consequence of the direct reduction by carbon dissolved in molten Fe-Cr-C alloy. The reduction of MgCr2O4 is sluggish at the later stage because of slower diffusion in the sintered layers of Cr-C alloy and MgO with high melting points.抄録全体を表示PDF形式でダウンロード (2465K) -
平井 伸治, 三輪 哲也, 岩田 努, 片山 博1990 年 54 巻 2 号 p. 181-185
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーExperiments were made of the effects of the kind, particle diameter and proportion ratio of raw material, and the addition of various substances on the formation of AlN through carbothermic reduction of Al2O3 in a flowing N2 atmosphere. The results are as follows: (1) The smaller the particle diameter of Al2O3 was, the higher became the reaction rate, but it decreased where the diameter was less than 0.7 μm. (2) When fine carbon black was used instead of graphite, a marked increase in reaction rate was observed. (3) With a pellet made of relatively coarse Al2O3 and graphite, the pellet diameter had little effect on the reaction rate, whereas in the case of fine particle, the rate decreased with the increase of pellet diameter. (4) The higher the proportion of carbon black, the greater became the degree of reaction. (5) When CaCl2, CaCN2, CaC2, CaF2, CaB4O7 and La each were added by 1 mass%, a marked acceleration effect was produced at the initial stage of reaction.抄録全体を表示PDF形式でダウンロード (703K) -
斎藤 秀俊, 弘津 禎彦, 一ノ瀬 幸雄1990 年 54 巻 2 号 p. 186-192
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーA new synthesis technique of boron nitride (BN) is described and formation conditions of cubic boron nitride (cBN) are discussed. Raw reactive gases B2H6+NH3+H2 were excited into plasma state by radio frequency (RF) induction of 13.56 MHz. The gas plasma was thermally activated by a hot tungsten filament and BN film was deposited on a Si substrate heated at an optimum temperature of 1073 K. Crystal structures of as-deposited films prepared under various deposition conditions were analysed by transmission electron microscopy and infrared absorption spectroscopy. The surface and cross-section of BN films were observed by scanning electron microscopy (SEM). It was found that the crystal structure of BN film strongly depends on the tungsten filament temperature, total gas pressure and RF power. SEM study showed that the film surface is smooth for t-BN but very rough for cBN. Many semisphere grains are seen on the surface of the cBN films and the grain size tends to increase with the increase of film thickness. According to a cross-sectional SEM study, the semisphere grains were found to be composed of columnar structures which grew perpendicularly to the substrate plane.抄録全体を表示PDF形式でダウンロード (2073K) -
須佐 匡裕, 篠原 秀幸, 永田 和宏, 後藤 和弘1990 年 54 巻 2 号 p. 193-200
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThe diffusivities of O2 molecules in amorphous SiO2 thin films were determined over the temperature range of 1073 to 1273 K by means of the thermal oxidation of Si substrates. The SiO2 films were synthesized on Si substrates with the four different methods, i.e., thermal oxidation, sputtering, chemical vapor deposition (CVD) and spin-on glass (SOG) methods.
The difference of the manufacturing methods changed the diffusivities and the activation energies. The diffusivity in the thermally-grown SiO2 films was determined to be 6.4×10−13 m2/s at 1273 K, which was the same with that in the sputtered SiO2 films. On the other hand, the diffusivities in the CVD- and the SOG-SiO2 films were determined to be 9.1×10−13 and 1.1×10−12 m2/s, respectively. The activation energies were calculated to be 113 kJ /mol for the thermally-grown and the sputtered films, 83 kJ /mol for the CVD films and 59 kJ/mol for the SOG films.
FT-IR (Fourier-transform infrared spectroscopy) spectra revealed the following. Both before and after the oxidation Si-H bond was observed in the CVD films. On the other hand, in the SOG films Si-(CH3)3 bond was observed.
The difference of the structures of the four SiO2 films was estimated as follows. The thermally-grown and the sputtered films are consisted of the continuous random network of SiO2. But in the CVD- and SOG-SiO2 films the random network structure is partially terminated with Si-H and Si-(CH3)3 bonds, respectively, which increases the mean dimensions of the unit cell of the network.抄録全体を表示PDF形式でダウンロード (1022K) -
佐藤 彰, 大沢 嘉昭, 荒金 吾郎1990 年 54 巻 2 号 p. 201-207
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーAl-Cu and Al-Si alloy round rods were experimentally produced by using a moldless upward continuous casting apparatus. Al-Cu and Al-Si alloys were selected because they have a wide solidification range and solidify in a mushy type or in a eutectic manner. Effects of the concentration of the alloying element, the superheat of molten metal, the upward withdrawal speed, and the strand rotation upon the diameter, the taper, the macrostructure, the microstructure, and the surface condition of the cast strand were investigated, with the following results.
The diameter and the taper of the alloy cast strand were determined by the superheat of the molten metal, the withdrawal speed and the strand cooling intensity, similar to those of aluminum having no solidification range and solidifying by skin formation. The cast strand consisted of columnar grains solidified completely unidirectionally. The diameter of the alloy cast strand was smaller than that of aluminum, which was considered to be due to the low heat conductivity of the alloy. The size of the dendrite observed in the cross section was proportional to the diameter of the cast strand despite of the different combination of the super-heat and the withdrawal speed.抄録全体を表示PDF形式でダウンロード (2255K) -
奥宮 正洋, 恒川 好樹, 新美 格, 亀田 弘之1990 年 54 巻 2 号 p. 208-213
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーPure iron and low-carbon steel (S15CK) foils were used as a specimen. Carbon and nitrogen contents in the furnace atmosphere of gas-carbonitriding were controlled by the dew point and retained ammonia, and the influence of temperature on the critical carbon and nitrogen contents for the formation of specific microstructures was studied. The specific microstructures were determined to be void, cementite, and graphite. The effects of the carbon and nitrogen contents on the mechanism of formation of the specific microstructures were discussed. In both kinds of specimen, the critical nitrogen content for formation of voids decreased with the treating temperature, and time. The critical carbon content for the formation of cementite or graphite increased with the treating temperature, but it was constant regardless of the treating time. The critical carbon content for the formation of cementite was practically unaffected by the nitrogen content. Under the same treating conditions, the critical carbon for the formation of cementite or graphite in pure iron and S15CK was nearly equal to each other. The critical nitrogen for the formation of void in pure iron was always lower than that in S15CK, because there were nonmetallic inclusions in S15CK and the austenite grain size was finer. In both specimens, graphite was formed only in the case of carbonitriding in which the nitrogen content was over about 0.1 mass%. Cementite existed whenever graphite was formed, and graphite existed mainly in and near cementite but sometimes at a distance. It appeared that nitrogen added to steels would afford the situation for formation of graphite in the solid phase and assist graphite formation.抄録全体を表示PDF形式でダウンロード (1218K) -
太田口 稔, 海江田 義也, 小黒 信高, 志手 秀司, 尾家 正1990 年 54 巻 2 号 p. 214-223
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーNiTi shape memory alloy is usually produced by the process including high frequency induction vacuum melting. The transformation temperature of the NiTi shape memory alloy is said difficult to be controlled precisely because the martensitic transformation temperature is changed by 10 K due to the change of 0.1 mass% of Ni content. In the present paper, it is reported that the NiTi intermetallic compound is synthesized by the combustion synthesis method, which is a newly developed manufacturing process, by controlling the content of Ni and Ti elemental powders. In the process, Ni and Ti powders are weighed and mixed to 50 at% of Ni by the dry ball mill. The mixed powder is filled in the graphite crucible and the top of the powder is ignited by heating with tungsten heater in vacuum (10−4 Pa) or argon gas atmosphere. Then the combustion synthesis of NiTi is self-propagated to the end of the powder. The synthesized NiTi is then sintered by hot isostatic press (HIP). The HIP’ped NiTi is plastically worked to the plate and wire. The ignition of the combustion synthesis is successful in high vacuum and argon gas atmosphere from room temperature to 873 K, and the chemical reaction is completely propagated. 100%NiTi intermetallic compound is observed by X-ray diffraction analysis in the combustion synthesized NiTi ignited at any temperature in the present experiment. As combustion-synthesized NiTi ingot is porous and the relative density is 50-60%, but after HIP’ping the relative density increased to 100%. The HIP’ped ingot is plastically worked with hot rolling, hot bar-rolling, hot and cold rotary-swaging and cold-drawing. When the oxygen content of the synthesized NiTi is about 0.5%, the 0.5 mm diameter wire is obtained. However, when the oxygen content is under 0.07%, a 0.09 mm diameter wire is achieved. The wire has the shape memory effect and the shape memory temperature of it is about 370 K.抄録全体を表示PDF形式でダウンロード (3627K) -
林 宏爾, 林 台煥1990 年 54 巻 2 号 p. 224-230
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThe densification behavior of carbonyl iron powder (5.3 μm; oxygen, 0.40 mass%; carbon, 0.03 mass%) in vacuum-sintering and the effects of added elements such as Al, Cr, Mn, Mo, Nb, Si, Ti, V and W on the behavior were investigated.
It was found that the densification of iron compact saturated near 94% of the theoretical density; the densification was incomplete. The addition of Al, Nb, Ti and V, or the use of special iron powder with very low carbon content resulted in the complete densification. These results could not be explained by well-known theories such as pore isolation from grain boundaries and liquid phase sintering. Taking into consideration the relation between the densification and the standard free energy for the formation of oxide of each added element, the incomplete densification of the carbonyl iron powder was attributed to the high value of the equilibrium pressure of CO gas which was formed by the reduction reaction of the iron oxide with carbon and was trapped in the closed pores in the sintered compact.抄録全体を表示PDF形式でダウンロード (2493K) -
末吉 秀一, 田中 良平1990 年 54 巻 2 号 p. 231-236
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーFor the purpose of developing a structural steel having both excellent plasticity and machinability in addition to a high tensile strength, heat-treatment for the tri-phase steel composed of ferrite, martensite, and graphite is examined and the machinability of the tri-phase steel is studied by comparing with that of the dual phase steel composed of ferrite and martensite. The results obtained are summarized as follows.
(1) By means of a series of three-stage heat-treatments constructed from quenching as pre-treatment, partial graphitization at a temperature just below A1, and quenching from a temperature just above A1, the tri-phase steel in which fine graphite nodules and fine martensite are dispersed in ferrite matrices can be obtained.
(2) The tri-phase steel is low in cutting force as compared with the dual phase steel because of the decreases of shear stress and friction angle and an increase of shear angle with the presence of the graphite nodules.
(3) The tri-phase steel is slightly inferrior to the dual phase steel in surface roughness after machining because the graphite nodules promotes the formation of micro-crack in the neighborhood of a tool edge.
(4) The drillability of the tri-phase steel is considerably superior to that of the dual phase steel.抄録全体を表示PDF形式でダウンロード (1695K) -
中村 裕司, 横山 雅, 中桐 明和, 前田 春興1990 年 54 巻 2 号 p. 237-243
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThe influence of elastic anisotropy and grain size on the stress distribution in β phase shape memory alloys has been analyzed by the FEM (Finite Element Method) stress analysis.
Results of the analysis for the single crystals showed that the largest strains appeared upon deformation along ⟨100⟩ directions, while the smallest along ⟨110⟩ directions. This means that the strains depend on the orientation of deformation. The ratios of the maximum strain/the minimum strain for the single crystals increased with increasing anisotropy factor A{=2×C44⁄(C11−C12)}.
For the case of the bicrystals, consisting of grains with orientations φ1, and φ2, the calculated stress concentration factors α for the grain boundaries showed the maxima at {φ1,φ2)=(0,π⁄4) or (π⁄4,0). The maximum values of stress concentration factor increased with increasing anisotropy factor.
For the case of the polycrystals, the variation coefficients (=the standard deviation/the average) for the Young’s moduli and the stress concentration factors increased with increasing anisotropy factor. While the average of the Young’s moduli and the stress concentration factors did not show clear dependence on grain size, their scatter increased with increasing grain size. This implies the existance of the large stress concentration along grain boundaries in the coarse-grained alloys.抄録全体を表示PDF形式でダウンロード (940K) -
成田 敏夫, 三枝 利紀, 石川 達雄1990 年 54 巻 2 号 p. 244-245
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーPDF形式でダウンロード (421K)
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