巻号一覧
56 巻, 8 号
選択された号の論文の17件中1～17を表示しています
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加藤 雅治, 藤居 俊之, 星野 安生, 森 勉1992 年 56 巻 8 号 p. 865
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThere are two different ways of understanding the stress effects on martensitic transformations. The most commonly accepted one is that the stress helps the total shape deformation of the transformation. The other is that the stress helps the shear deformation involved in the lattice change. To find out which one is more reasonable, critical experiments were conducted to examine the stress-induced γ→α martensitic transformation in small Fe particles in Cu single crystals. The amount of transformed α-Fe particles was also examined as a function of plastic strain. It has been found that specific Kurdjumov-Sachs variants out of 24 crystallographically equivalent ones are formed preferentially depending on the direction ([001] or [419]) and sense (tension or compression) of the applied stress. Although tension induced more martensites than compression in polycrystalline specimens, the converse was found to be the case for the single-crystalline specimens stressed along [001] and no significant difference in the amount of transformed particles between tension and compression was detected for the specimens stressed along [419]. These experimental results were analyzed in the light of the theoretical expectations based on the two ways of understanding the stress effect. It has been found that the experimental results can be understood very reasonably if the significant stress effect on the f.c.c. to b.c.c. lattice change is considered.抄録全体を表示PDF形式でダウンロード (2084K) -
吉村 敏彦, 石川 雄一1992 年 56 巻 8 号 p. 873-880
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe ferritic phase decomposition of thermally aged ferritic/austenitic duplex stainless steels has been examined layer by layer by a pulsed laser-atom probe. In this study Fe-25%Cr-6%Ni-3%Mo duplex steel (SUS329J2L) was aged at 450°C for up to 5000 h. The results obtained are as follows: (1) The initial fluctuation of Cr concentration increases by ageing at 450°C for 100 h. At the ageing time of 1000 h the fluctuation further increases and the α′ phase with Cr concentration of 65% precipitates. (2) The α′ phase is believed to be formed by spinodal decomposition. (3) In the material aged for 1000 h, the average particle size of α′ particles ranges from 0.6 to 1.1 nm and the wave length from 1,8 to 4.0 nm. (4) Ni tends to segregate into the Cr-depleted region between the α′ phases. (5) Ni-Si-Mo clustering is recognized in the ferritic phase prior to formation of the α′ phase. (6) At 5000 h the particle size and the wave length increase due to the aggregation of α′ phase. This results in decrease of hardness.抄録全体を表示PDF形式でダウンロード (1248K) -
稲葉 輝彦, 飴山 惠, 時実 正治1992 年 56 巻 8 号 p. 881-888
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe morphology and crystallographic features of triangular-α phase precipitated from β matrix in a Ti-15V-3Cr-3Sn-3Al alloy have been studied by scanning and transmission electron microscopy. The β single-phase material was prepared by heating the alloy above the β transus temperature followed by quenching in water, and subsequent two-step aging at 573 K and 813 K. After the aging, a film-like or allotriomorph intergranular α phase and a triangular-shaped intragranular α phase are observed. The three-dimensional shape of the triangular-α phase is a triangular pyramid consisting of three α precipitates. Each α phase of the pyramid is found to have not only Burgers orientation relationship with β matrix but also a near twin relationship with the other α precipitates of the pyramid at the same time. There is particular Burgers variants allowed to form a near twin related triangular pyramid. The crystallographic features which satisfy the above two conditions, i. e., Burgers orientation relationship and a near twin relation, strongly suggest that the triangular-α phase is formed by the sympathetic nucleation of α precipitates.抄録全体を表示PDF形式でダウンロード (1886K) -
山村 力, 水野 茂, 仁藤 丈裕, 遠藤 守, 佐藤 譲, 江島 辰彦1992 年 56 巻 8 号 p. 889-896
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe refractive indicies of ZnCl2-MCl(M : Li, Na and K) binary melts have been measured at the wave lengths of 420 to 670 nm, over the entire comoposition range and at the temperatures ranging from the liquidus temperatures to 200 K above them. A minimum deviation angle method was used for the measurement. The correlation between the composition change in refractive index and the melt structure has been studied. The results can be summarized as follows:
The wave length dependence of refractive index is typical of normal dispersion. The composition dependence of the refractive index has been found to be closely correlated with that of the molar volume. It is considered that the number densities of constituent ions are the most important factors which control the temperature and composition dependence of the refractive index.
The electronic polarizabilities of salts have been determined from the refractive indicies by the use of the Clausius-Mossotti equation. Electronic polarizabilities of the binary melts show small deviations from the additive rule. The temperature dependence of the electronic polarizability has been attributed to the change of the constituent species in the melts.抄録全体を表示PDF形式でダウンロード (1092K) -
一色 実, Kékesi Tamás, 増本 剛1992 年 56 巻 8 号 p. 897-899
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe anion exchange method in a hydrochloric acid solution was applied for the preparation of high purity copper using CuCl as a starting material. The purified copper chloride solution was evaporated to dryness and reduced by hydrogen. After arc-melting, specimens with the dimensions of 0.5×1.0×20 mm3 were prepared by cold rolling and subjected to the annealing process which consists of heating in dry hydrogen for 20 h and in vacuum for 20 h at 873 K. The residual resistivity ratio of purified copper was 1470, while that of the copper prepared directly from the starting material and treated in the same way was 36. This result revealed that the anion exchange method is very effective for the preparation of high purity copper.抄録全体を表示PDF形式でダウンロード (411K) -
亀田 和夫, 山口 勉功, 昆 利子1992 年 56 巻 8 号 p. 900-906
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe emf measurements of the following galvanic cells have been carried out to determine the standard free energy of formation of Bi2O3(s) and the thermodynamic quantities of liquid Tl-Bi alloys:
(This article is not displayable. Please see full text pdf.)
The standard free energy of formation of Bi2O3(s) are determined as follows:
(This article is not displayable. Please see full text pdf.)
The activities of both components in liquid Tl-Bi alloys at 850 and 950 K deviate to negative from Raoult’s law over the whole concentration ranges and agree well with the previous results. The γ°Bi and γ°Tl values are estimated to be 0.031 and 0.17 at 850 K and 0.037 and 0.20 at 950 K, respectively. The α function of bismuth against NBi does not show a constant value, suggesting no regular solution behavior in the system.
The free energy of mixing at 850 K shows negative values than ΔGid, and the peak value of ΔG is −9.3 kJ/mol at about NBi=0.46. The heat of mixing also shows negative values. The peak value of ΔH is −4.4 kJ/mol at about NBi=0.40.抄録全体を表示PDF形式でダウンロード (945K) -
三村 耕司, 春日 倫弘, 南條 道夫1992 年 56 巻 8 号 p. 907-914
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーRemoval of non-metallic and metallic impurities from niobium rods of 5 mm diameter has been examined by the electron beam floating zone melting (EBFZM) technique in a high vacuum.
The oxygen and carbon contents rapidly decreased to the very low level of 0.02 and 0.3 mass ppm respectively, after seven zone passes at 2 mm/min zoning speed. The nitrogen content, however, showed a gradual decrease attaining a level of 5 mass ppm. This behavior can be attributed to the slow rate of denitrogenization. The considerably high extent of deoxidation was probably due to the fast evaporation of niobium suboxide (NbO) with CO-degassing. Since decarburization is the result of the CO gas evolution, further reduction of the carbon concentration could be expected under the condition of a higher ratio of oxygen to carbon. Most of the metallic impurities such as iron and nickel, being more volatile than niobium, volatilized preferentially and their contents were reduced to below 5 mass ppm. While the concentrations of tantalum and tungsten, characterized by a lower volatility than niobium, showed almost no decreases and their redistribution were not observed because the corresponding effective distribution coefficients were close to unity, even when the zoning speed was as low as 0.1 mm/min. As a result of the remarkable reduction of the non-metallic impurities by the EBFZM treatment, the mean Vickers hardness number of the zone melted niobium was reduced to be under 50 Hv.抄録全体を表示PDF形式でダウンロード (1485K) -
砂田 聡, 高野 智, 大塚 公輝, 三股 隆, 佐貫 須美子, 新井 甲一1992 年 56 巻 8 号 p. 915-922
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe effect of carbon content on the general corrosion behavior for SCS11 casting duplex stainless steels in a dilute solution is discussed on the basis of the experimental results obtained by the measurements of anodic polarization curves, determination of dissolved species in the solution, SEM observation of corrosion surface and X-ray diffraction analysis.
The main results obtained are summarized as follows:
(1)The corrosion rate of SCS11 casting duplex stainless steels in the active region increases with an increase in the concentration of H2SO4, the solution temperature and the carbon content. The corrosion of ferrite phase is larger than that of the austenite phase. However, there is little effect of carbon content on the corrosion behavior in the passivation region.
(2)The M23C6 carbide is deposited around the boundary layer between the austenite and ferrite phases. The surface area ratio of carbide increases with an increase in the carbon content, and the corrosion rate in the active region is enhanced in proportion to the surface area ratio of carbide.
(3)The increase of the corrosion rate may be caused by the formation of a galvanic couple between the precipitated carbide and its matrix phase. The corrosion of SCS11 casting duplex stainless steels proceeds simultaneously with the preferential dissolution of ferrite phase and the galvanic corrosion in the active region.抄録全体を表示PDF形式でダウンロード (2977K) -
小池 精一, 窪田 隆一, 市川 政夫, 馬場 剛志, 高橋 和也1992 年 56 巻 8 号 p. 923-929
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe rapid solidification of aluminum powder is the most fundamental process in the production of P/M materials. This process must be clearly understood since it directly affects the properties of materials and their production costs. In this study, Al-6Cr-3Fe-2Zr alloy powder, originally developed as a heat-resistant aluminum alloy, has been produced by using two different gas atomization processes involving high- and low- pressure gas atomization, thus enabling more efficient industrial production of powder with a rapid cooling rate. The effects of gas atomization factors on the particle shape, size distribution, surface oxidation and microstructure of the as-atomized particles have been investigated. In addition, these effects on the mechanical properties of materials formed through powder extrusion have been evaluated.
It is found that the particle shape varied with the surface layer of aluminum oxide, which was about 10 nm thick. Atomizing under high-pressure helium reduced the average particle diameter to 18 μm with an excellent size distribution. Particle microstructures largely depend on the particle size and type of the atomizing gas used. The use of helium produced the finest particle microstructure made of Al-Cr-Fe and Al-Zr system dispersoids. The extruded alloy, formed from −25 μm powders which were atomized under high-pressure helium, showed an outstanding tensile strength of 584 MPa at room temperature and 300 MPa at 300°C.抄録全体を表示PDF形式でダウンロード (2066K) -
水内 潔, 大神田 佳平, 大中 逸雄1992 年 56 巻 8 号 p. 930-937
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーRapidly solidified Fe-30Cr-5Al alloy powders containing Ce up to 0.69 mass% produced by the Rotating-Water-Atomization Process were sintered and sheath-rolled. Rapidly solidified powders without Ce could be well sintered at temperatures more than 1673 K for time more than 3.6 ks. The grain size grew from 20 to 30 mm after annealing at 1673 K for 14.4 ks. The tensile strength of compacted Fe-30Cr-5Al powder was in the range from 350 to 450 MPa, and the elongation was in the range from 2 to 3%. The surface oxidation of particle was increased with the addition of Ce. However, it was suppressed in the Rotating-Water-Atomization under Ar atmosphere. The tensile strength of sheath-rolled Fe-30Cr-5Al-0.69Ce powder was 210 MPa. The tensile strength of compacted powders was superior to that of the as-cast material.抄録全体を表示PDF形式でダウンロード (3638K) -
山田 修, 宮本 欽生1992 年 56 巻 8 号 p. 938-942
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーA new process for intermetallic compounds has been developed by combining the thermite reaction and the combustion synthesis reaction. The process enables to produce many compounds such as Ni-Ti, Ni-Al and Fe-Al from mixed reactants of metal oxide, metal and/or semi-metal without external heat supply. In the case of 6NiO+8Ni+18Al⇒14NiAl+2Al2O3, the combustion temperature exceeds the melting points of both products and the fused NiAl is solidified separately from Al2O3 due to the density difference. This new process would be used for castings of intermetallics and ceramic composites.抄録全体を表示PDF形式でダウンロード (1272K) -
三浦 誠司, 栗山 春宣, 三島 良直, 鈴木 朝夫1992 年 56 巻 8 号 p. 943-951
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーSingle crystalline Co3Ti base quarternary compounds, (Co, Ni)3(Ti, Al), are prepared and the effects of temperature, strain rate and orientation on the plastic behavior are investigated. Then the results are compared to other L12 intermetallic compounds being represented by Ni3Al. The differences found by the comparison are as follows. (1) Regardless of the crystallographic orientation with respect to the stress axis, there is a strong negative temperature dependence of strength at low temperature regime. (2) Plastic deformation is accompanied by serration on the stress strain curve and by metallic acoustic emission in the single crystals with near-[111] orientation and at temperature regime between 77 to 973 K where the anomalous positive temperature dependence of strength is observed. (3) For the same orientations, the temperature regime where cube slip governs the plastic deformation is narrow. (4) Octahedral viscous flow at the high temperature regime is not associated with well-defined yield drop. It is to be noted that the plastic behavior of Co3Ti base single crystals should also be discussed seperately in the above four regimes as has been done in other single crystalline L12 compounds.抄録全体を表示PDF形式でダウンロード (1251K) -
崔 判圭, 井野 博満, 木戸 義勇1992 年 56 巻 8 号 p. 952-959
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーWe have studied the effect of C, Al and Si additions on magnetic properties of melt-spun Nd-Fe-B permanent magnet alloys. The compositions of the alloys were chosen to be Fe77.5Nd15(B1−xMx)7.5(M=C, Al, Si), 0.1≤x≤0.4. The crystallization temperature of the melt-spun amorphous alloys increased with increasing concentration of the forth elements M. The Curie temperature of the Nd2Fe14B phase increased with increasing concentration of Si, whereas it decreased with C and Al.
The addition of the forth elements improved the magnetic properties. In the case of C addition, the intrinsic coercive field iHc was little changed compared with the ternary alloy, but the remanence Br showed high values in the composition range from x=0.15 to x=0.25, and the maximum energy product (BH)max was 1.6 to 1.8 times larger than that of the ternary alloy, which reached to maximal 93 kJ/m3(11.5 MGOe). In the case of Al, iHc was maximal 1.55 MA/m (19.5 kOe) in the range from x=0.15 to x=0.3, Br and (BH)max showed high values all over the range. Br and (BH)max showed high values also in the case of Si.
The alloys, Fe77.5Nd15Al7.5 and Fe77.5Nd15Si7.5, showed poor hard magnetic properties, in which the Nd2Fe14M phase did not appear. Instead, Fe77.5Nd15C7.5 alloy showed a high iHc value(0.7 MA/m) in the specimen heat-treated at 1073 K, where the Nd2Fe14C phase was clearly observed.
It is concluded from the variation of relative intensities of peaks of Mössbauer spectra that Al and Si atoms were preferentially substituted for one or two (k2 and probably j2) iron sites in the Nd2Fe14B phase, and C atoms occupied the B atom positions.抄録全体を表示PDF形式でダウンロード (942K) -
斎藤 栄, 和知 高志, 安達 和彦, 花田 修治1992 年 56 巻 8 号 p. 960-964
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe Clad-Chip Extrusion (CCE) method is applied to a fabrication process of Nb3Sn superconducting wires. This method is characterized by extruding the chipped Nb-Sn clad sheets with the intended chemical composition. Ti-foil cladding to the Nb-Sn composite sheet is also studied as a method of titanium addition. An extruded Nb-Sn composite bar shows good workability in wire drawing up to a relatively high reduction ratio, R of 106, where R is the cross-section ratio of an initial billet to a final wire.
The CCE-processed Nb3Sn wire heat-treated under the optimum condition shows the critical transition temperature, Tc of 17.8 K and the critical current density, Jc of 1.18×108 A·m−2 in the applied magnetic field of 20 T at 4.2 K. The upper critical field, B∗c2 (4.2 K) is estimated as 23.4 T using the Kramer plot.抄録全体を表示PDF形式でダウンロード (1002K) -
藤谷 伸, 安山 茂幸, 古川 明男, 米崎 孝広, 名迫 賢二, 米津 育郎, 斎藤 俊彦1992 年 56 巻 8 号 p. 965-972
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe pressure-composition (P-C) isotherm of hydrogen in alloys is important for the practical use of hydrogen-absorbing alloys. A numerical expression method was developed for the plateau region of the P-C isotherm in LaNi5, LaNi4.8Mn0.2 and La0.8Y0.2Ni5 alloys with the CaCu5 structure.
Samples were prepared by using argon arc melting and annealing. The desorption isotherms at 298 K were used for testing the numerical expression. The regular solution model with a term proportional to hydrogen composition as an excess chemical potential was applied to the solid solution and hydride phase region. A normal cummulative distribution function (ncdf) model with composition as frequency was applied to the plateau region.
All the isotherms were expressed accurately with the models employed and characteristic parameters of the alloys were obtained. The changes in the micro-structural heterogeneity in the alloys by annealing and the Mn or Y substitution were in accordance with those in the standard deviation (σ) of the ncdf which presents the plateau slopes.
Consequently, the normal cummulative distribution function model for the plateau region was found to be helpful for the development of the alloys because σ presents both the plateau slope and the micro-structural heterogeneity in the alloys.抄録全体を表示PDF形式でダウンロード (1860K) -
大中 逸雄, 山内 勇, 板屋 光彦1992 年 56 巻 8 号 p. 973-981
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーTo improve the catalytic activity of Raney copper catalysts for the hydration reaction of acrylonitrile which is important for producing acrylamide, their mother alloys, namely Cu-70 at%Al alloys, with and without additive elements, were solidified at various cooling rates, and the structures of the mother alloys and catalysts made by leaching Al from them were examined by SEM, TEM and X-ray microanalysis. The specific surface area of the catalysts was measured by the BET nitrogen-absorption technique. The activity of the catalysts was evaluated by the conversion ratio from acrylonitrile to acrylamide by the hydration reaction. As a result, a drastic increase of the catalytic activity up to about 1.8 times as high as conventional Raney copper was realized by adding 0.8 at% of Ti or 0.7 at% of V and rapid solidification using the rotating-water-atomization process, while the cooling effect was smaller in the case of V addition. The TEM and chemical analysis revealed that the catalysts are aggregates of fine copper fibers 10 to 40 nm in diameter, containing 1 to 6 at%Al which increased by adding the third elements. The amount of residual additive elements increased with solidification rate. The catalytic activity improvement is attributed at least to the refinement of the Cu-fiber size. Further, the X-ray broadening method may underestimate the Cu-fiber size.抄録全体を表示PDF形式でダウンロード (3988K) -
小野 勝敏1992 年 56 巻 8 号 p. 982-983
発行日: 1992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 (430K)
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