巻号一覧
53 巻, 3 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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塚本 武彦, 小山 晋之, 太田 昭男, 野口 精一郎1989 年 53 巻 3 号 p. 253-257
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーThe structural transformation from the cubic to tetragonal phase has been studied in near-equiatomic M-Ru (M=V, Nb, Ta) alloys through the measurements of electrical resistivity, Hall coefficient and low-temperature specific heat. The transformation temperature TL decreases with decreasing Ru concentration. The values of TL for the binary V-Ru system and the pseudobinary V-Ti-Ru system are universally dependent on the electron-atom ratio Z, indicating the electronic transition. On the other hand, for pseudobinary M-Ti-Ru (M=Nb, Ta) systems, the TL values are not expressed as universal functions of Z. The Hall coefficient RH for V50+xRu50−x alloys decreases in the tetragonal phase, while it increases in the cubic phase with increasing the composition x, showing a minimum at the boundary composition between the cubic and tetragonal phases. For Nb50+xRu50−x and Ta50+xRu50−x alloys, on the contrary, the RH decreases monotonically with increasing x, showing no peak at the boundary composition. The value of electronic specific-heat coefficient γ for V54Ru46 is 7.5 mJ·mol−1·K−2, which is 4.2 times γ for Nb54Ru46 and 7.5 times γ for Ta54Ru46. The values of Debye temperature θD turn out to be 420 K for V54Ru46, 370 K for Nb54Ru46 and 320 K for Ta54Ru46. These results mean that the transformation for V-Ru alloys is caused by the band Jahn-Teller effect, while the one for Nb-Ru and Ta-Ru alloys is mainly caused by the lattice interaction.抄録全体を表示PDF形式でダウンロード (369K) -
北野 葉子, 前田 干寿子, 清水 真人, 小林 真司, 森戸 延行1989 年 53 巻 3 号 p. 258-265
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーSome experimental results by X-ray diffraction and Mössbauer spectroscopy are presented as to the annealing temperature dependence of AC magnetic properties in Fe78.5B13Si8.5 amorphous alloy.
The best values of the iron loss, W13⁄50, and the magnetic flux density at 100 A/m, B1 have been obtained after annealing at 673 K, which is below the Curie temperature 685 K of the amorphous alloy. Surface crystallization into α-Fe has been found to take place on the roll-side surface during annealing at temperatures above 698 K for 3.6 ks. Structural relaxation by annealing makes some peaks in radial distribution function (RDF) sharp and increases monotonously their peak heights with the rise of annealing temperature up to 723 K. The change in the in-plane magnetic anisotropy by annealing corresponds well with the change in the AC magnetic properties, and the biggest in-plane magnetic anisotropy is formed after annealing at 648-673 K.
It is suggested that the improvement of the magnetic properties by annealing at temperatures below 673 K is due to the stress relaxation, and that the deterioration above 673 K is due to the decreases in the in-plane magnetic anisotropy by annealing in a paramagnetic state and by compressive stress from the crystalline α-Fe surface layer formed during annealing.抄録全体を表示PDF形式でダウンロード (598K) -
趙 丕植, 小坂井 孝生, 宮崎 亨1989 年 53 巻 3 号 p. 266-272
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーProcesses of phase separations into A2 and DO3 at 773 K in Fe-Al-V ternary ordertng alloys were investigated by means of transmission electron microscopy. Sequences of phase separation from the A2, B2 or DO3 single phase state into the A2+DO3 equilibrium state were classified into three types. (1) In the alloys near the phase boundary A2/A2+DO3, the phase separation of A2 into A2+DO3 occurs directly without through any intermediate state. (2) In the alloys whose compositions are located in the centre area of the A2+DO3 field, phase decomposition from B2 into B2+DO3 arises, followed by the phase separation into A2+DO3. (3) In the alloys near the boundary between DO3/A2+DO3, continuous ordering from the B2 to DO3 phase occurs at first, and then A2 phase is formed on the antiphase boundaries of the DO3 phase. Finally, small particles of A2 precipitate in the ordered domains of the DO3 matrix. These sequences of phase separations could be explained from the hierarchy of free energies among the A2, B2 and DO3 phases.抄録全体を表示PDF形式でダウンロード (1335K) -
高山 善匡, 杜澤 達美, 加藤 一, 古城 紀雄, 堀 茂徳1989 年 53 巻 3 号 p. 273-280
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーThe change in the grain size distribution during grain growth has been investigated for a dual-phase brass. The two-dimensional grain size distribution, namely, that of grain intersect areas was measured. The distribution was also calculated for a sphere grain structure model. The model assumes that the grain diameter (=the equivalent volume diameter) D has a log-normal distribution; the distribution of this grain diameter is clearly defined by the geometric mean grain diameter Dg and the standard deviation of lnD, that is lnσg. The change of the grain diameter distribution was discussed qualitatively by comparing the experimental and the calculated results. The distribution is one of the expressions for the three-dimensional grain size distribution, the change of which corresponds directry to grain growth.
As a result, the mean grain intersect area increased during grain growth. The grain growth exponent n was not constant but decresed remarkably. The grain intersect area distributions of the α-, the β- and the dual phases were close to a log-normal distribution. The distribution for the model was not log normal strictly, and the deviation from the log-normal depended strongly on the value of lnσg. These results suggest that the value of lnσg for the α-phase remains relatively small, while that for the β-phase decreased during a short time heating and then remained almost constant.抄録全体を表示PDF形式でダウンロード (840K) -
猪子 富久治, 栗本 政雄, 永友 孝尚1989 年 53 巻 3 号 p. 281-289
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーIn order to clarify the influence of the grip effect on the formation of deformation bands, aluminum single crystals were deformed in tension by using an apparatus which can change the ratio of the horizontal velocity of the lower grip to the vertical one Vx⁄Vz. The relations between the deformation bands and the formation of recrystallized grains were examined.
The results obtained were as follows: (1) The grip effect was limited within the regions near the upper and the lower grips. (2) In the gauge length of all the specimens the deformation bands were formed with almost the constant number of 50 per 20 mm at the tensile strain around 3×10−1, even though the values of Vx⁄Vz was changed. In every specimen the angles between the specimen axis and both the deformation band and the primary slip band were approximately π/6 rad. (3) The formation of the deformation bands in the gauge length of the specimens did not depend on the grip effect, but on the intrinsic properties such as sub-boundaries. (4) The recrystallized grains were nucleated along the deformation bands. Their orientatxons were realized mainly by the rotation of deformed matrix about either one of the normals to four {111}. Among them the rotation about the normal to the primary slip plane was dominant.抄録全体を表示PDF形式でダウンロード (1133K) -
大橋 鉄也1989 年 53 巻 3 号 p. 290-295
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーNumerical models of face centered cubic single crystals, in which the condition for plastic slip is spacially non-uniform, have been developed. Tensile deformations of the models have been analysed by the finite element method. The evolutions of deformation bands from the initial non-uniformity and the characteristics of disordered stress field caused by non-uniform slip have been discussed. The results are as follows:
(1) non-uniformity in the distribution of the initial dislocation density caused the generation of a kink band even if the non-uniformity is very slight.
(2) a band of secondary slip is formed when the non-uniformity in the distribution of shear strain on the primary slip system reaches a certain value which is supposed to depend on the crystal orientation.
On the basis of the results of disordered stress field analyses, the reason for which the kink band and the band of secondary slip are formed in a specific direction has been discussed.抄録全体を表示PDF形式でダウンロード (612K) -
葉 英華, 宮地 正和, 中島 英治, 栗下 裕明, 後藤 正治, 吉永 日出男1989 年 53 巻 3 号 p. 296-302
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーIn order to examine the Srolovitz’s theory of attractive interaction between dislocations and dispersed particles, an Al-3.1 at%Mg-1.3 vol%Be alloy having effects of dispersion- and solution-hardening was subjected to creep tests and transmission electron microscopic observation. The creep test was conducted at temperatures from 623 to 723 K and it stresses from 1.8 to 51.4 MPa, which correspond to the range of 0.38∼8.48σv (σv is the void hardening stress).
The results show that the dislocation-particle interaction is attractive, but no clear threshold stress occurs under the conditions tested. This suggests that the absence of threshold stress may not be evidence of the climb mechanism. The reason for the absence of threshold stress in this alloy is discussed from viewpoints of solution-hardening and grain-boundary sliding.抄録全体を表示PDF形式でダウンロード (810K) -
永井 武, 名取 勝英, 古沢 孝1989 年 53 巻 3 号 p. 303-307
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーSpecimens of Zn electroplated cold-rolled steel plate have been exposed for approximately 6 years.
Nucleation and growth of Zn whiskers on specimens were observed visually, and the number of days before whiskers were detected was obtained.
Micro internal stress of Zn electroplate were measured by the Hall plot method using an X-ray diffractometer. The macro internal stress were measured by X-rays and the bending strain method. These results were compared with the number of days before whiskers were detected. A corelation was found between the number of days before whiskers were detected and the macro internal stress measured by the bending strain method.
The number and length of whiskers were counted and measured, and then the rate of short circuit caused by whisker was calculated.
As a result it was found that the rate of short circuit by whisker growth was c.a. 9 fit.抄録全体を表示PDF形式でダウンロード (450K) -
張 時性, 沼田 博雄, 大野 湶, 春山 志郎1989 年 53 巻 3 号 p. 308-313
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーElectrochemical polarization experiments were made on the liquid and solid gallium electrodes in acidic sulfate solutions of pH 1.0∼3.0 over the temperature range of 288∼313 K. The cathodic polarization curves for hydrogen evolution on gallium exhibited a Tafel line with the slope of 0.12 V/decade in a limited range of current density. The exchange current densities were of the order of 10−5 A/m2 and their Arrehnius plots yielded a straight line which gave the apparent activation energy of 46.2 kJ/mol. No dramatic changes in the kinetics were observed at the melting point of gallium. The hydrogen evolution on gallium is probably controlled by charge transfer step. The anodic polarization curves on gallium were poorly dependent on the potential. It is likely that the anodic dissolution of gallium takes place via the formation of less-protective Ga2O3 film on the surface. Especially on a liquid gallium electrode, the anodic current increased steeply at −0.1 V (SCE), probably because of spalling of the anodic film.
The rate of corrosion of gallium in acidic sulfate solution was of the order of 0.3 A/m2 and increased with decreasing the pH value and increasing temperature. There were no specific changes in the corrosion rate above and below the melting point of gallium.抄録全体を表示PDF形式でダウンロード (474K) -
秋山 哲也, 寺崎 俊夫1989 年 53 巻 3 号 p. 314-321
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーThe phenomena of the sensitization of a base metal and the method to predict the time when the degree of sensitization of the base metal exceeds a critical value were investigated by comparing the degree of sensitization of the base metal and that of the welded heat affected zone (HAZ).
To compare these sensitizations, mathematical analysis and experimental tests were carried out. The materials used in this experiment were type 304 stainless steel plates having 10 and 30% plastic strains. To determine the degree of sensitization, the EPR test was used.
From the mathematical analysis, the following results were obtained. In the case where the materials had a plastic strain of above 3%, the degree of sensitization of the base metal became larger than that of the heat affected zone.
From the experimental tests, the following results were obtained. The degree of sensitization of the base metal became larger than that of the heat affected zone. However, in the case where the hardness of the base metal became smaller to a level of the HAZ with the prolonged time for the low temperature sensitization, this phenomenon disappeared.
For the materials having 10 or 30% plastic strain, we were able to predict the time needed for the degree of sensitization of the base metal to exceed the critical value.抄録全体を表示PDF形式でダウンロード (904K) -
水野 忠彦1989 年 53 巻 3 号 p. 322-326
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーPitting corrosion of pure iron in borate buffer solution was studied by in-situ technics using chloride isotope 36Cl. Relationships between chloride ion concentration and current density in pit during pitting corrosion was discussed. Some results are summarized as follows.
(1) Pits growth process is divided into two steps by the variation of chloride ion concentration and pitting current with time.
The first step: chloride ion concentration on a pit surface (γp) increases linearly with time while the current density (ip) stays constant.
The second step: γp stays at a constant, on the other hand, ip decreases gradually with time.
(2) Both of γp and ip increase with external electrode potential.
(3) Also γp and ip increase with a logarithmic low of the chloride ion concentration in a bulk solution.抄録全体を表示PDF形式でダウンロード (399K) -
生野 元, 砥綿 真一, 山田 銑一1989 年 53 巻 3 号 p. 327-332
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーHybrid Fiber-Reinforced-Metals (FRMs), in which particulates and whiskers were distributed among the continuous fibers, were prepared by squeeze casting process.
Pure aluminum and Al-5%Mg alloy were used as the matrix metal. The residual expansions were measured and the transverse strength after thermal cyclings between room temperature and 573 K were evaluated. The effects of hybrid technique and alloying element Mg on the thermal fatigue behavior of FRMs were investigated.
The results are as follows:
(1) Approximately 1% of strain of transverse residual expansion was observed after thermal cycling of 1000 times. Aluminum-magnesium matrix composites expanded linearly, while pure aluminum matrix ones expanded nonlinearly.
(2) A lot of cracks between fiber and matrix were observed after thermal cycling. In the case of the non-hybrid composites, many fiber-to-fiber contacts were observed because the fibers were closely packed by the pressure of the molten metal. On the other hand, in the case of the hybrid composites, few fiber-to-fiber contacts were observed because particulates or whiskers existed around the fibers. So, some cracks were connected through fiber-to-fiber contact points for the non-hybrid composites in contrast with cracks separated around each of fibers for the hybrid ones.
(3) During thermal cycling of aluminum-magnesium matrix composites, the transverse strength of the composites was promptly degraded from 100 to 80 MPa for the hybrid composites and it gradually fell down from 45 to 30 MPa for the non-hybrid ones.
(4) Few fibers debonded from matrix of hybrid composites on transverse fracture surfaces in contrast with the non-hybrid composites which indicated a lot of debonded fibers.抄録全体を表示PDF形式でダウンロード (627K) -
斎藤 栄, 池田 圭介, 永田 明彦, 和泉 修1989 年 53 巻 3 号 p. 333-338
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーThe fabrication process of Nb3Al superconducting wires by the infiltration method was investigated in detail.
For powder size, niobium powder with a sieve range of −200+250 mesh was successfully used to obtain cold isostatic pressed and sintered niobium rods with a desired level of porosity that were later infiltrated with liquid aluminum.
For infiltration, the temperature range of 963∼973 K and the immersion time of 180∼300 s were preferred in order to prevent the formation of brittle intermediate phases which could impair the ductility of the Nb-Al composite.
The sheath material needed to have higher flow stress than that of the composite for successful drawing.
The critical current density of finished wire was measured under the magnetic field up to 15 tesla. The wire with the Nb-rich composition showed excellent Jc-H properties among the ones with a wide range of Nb-Al compositions studied in this investigation.抄録全体を表示PDF形式でダウンロード (836K) -
香川 豊, 崔 培浩1989 年 53 巻 3 号 p. 339-348
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーThe effects of mechanical properties of a matrix on the tensile strength and fracture toughness of brittle fiber-reinforced metal matrix cpmposites have been investigated. Unidirectionally aligned continuous SiC fiber-reinforced composites with commercially pure aluminum matrix (SiC/CPA1) and aluminum alloy matrix (SiC/A384), both unnotched and notched specimens, were tensile-tested. Their failure behavior and the relation between tensile strength and nonlinear energy fracture toughness of the composites were examined.
The tensile strength and fracture toughness of SiC/CPA1 composite increased with increasing fiber volume fraction, while those of SiC/A384 composite decreased. There was a strong correlation between tensile strength and fracture toughness in the composites; the tensile strength increased proportionally with increasing fracture toughness. SiC fibers extracted from both composites were equal in atrength and scatter, and the interfacial strengths of the composites were interpreted to be sufficiently high for preventing stress relaxation by interfacial debonding. Such a difference of the fracture behavior would be due to the difference of the stress ralaxation mechanism following the initial fracture of weak fibers in the matrix metals. The present results meet the well-known concept that ductile and notch insensitive metal for the matrix is recommended to obtain a high strength composite using full potential of a brittle fiber.抄録全体を表示PDF形式でダウンロード (1277K) -
高橋 秀之, 奥村 豊彦, 瀬尾 芳弘1989 年 53 巻 3 号 p. 349-355
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーHigh Tc superconducting materials of the Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O systems usually consist of many phases which are about few micron meters in size and are different from each other in composition. Analysis of many phases with EPMA confirmed that the superconducting phase is Y1Ba2Cu3O7−δ.
Valence states of the Cu-O bond depend on superconducting states. It was made clear that the shapes and energies of O-Kα peaks largely depend on the types of crystal structures. This result indicated that the superconducting phase and the incomplete reaction phase are the perovskite and another crystal type, respectively. Moreover, the Cu valence of the Y-Ba-Cu-O superconductive phase was estimated to be +2.4 from the measured peak ratio Cu-Lβ/Lα related to Cu Valences.抄録全体を表示PDF形式でダウンロード (1303K) -
稲葉 道彦, 野村 貴美, 氏平 祐輔1989 年 53 巻 3 号 p. 356-357
発行日: 1989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 (244K) -
1989 年 53 巻 3 号 p. 358
発行日: 1989年
公開日: 2008/04/04
ジャーナル フリーPDFを参照． （誤）Fig. 5 Examples of cell structure observed in ruptured alloy N specimens. (a) 118 MPa, 1089 K, tr=1645 ks, (b) 29.4 MPa, 1311 K, tr=540 ks. (tr: rupture life) （正）Fig. 5 Examples of cell structure observed in ruptured specimens. (a) alloy N (118 MPa, 1089 K, tr=1645 ks), (b) alloy S (29.4 MPa, 1311 K, tr=683 ks). (tr: rupture life)抄録全体を表示PDF形式でダウンロード (19K)
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