巻号一覧
55 巻, 10 号
選択された号の論文の16件中1～16を表示しています
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京武 順, 武末 尚久, 森永 正彦, 湯川 夏夫1991 年 55 巻 10 号 p. 1031-1038
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーA first computer method has been proposed for the simulation of the local atomic displacement in alloys. Employing a Monte Carlo method the simulation has been carried out so that the local displacement parameters determined experimentally from diffuse-scattering measurements fit the simulationed ones. A whole feature of atomic fluctuations can be spacified by combining this method with Gehlen-Cohen method for the chemical short-range order in alloys.
This method has been applied to the structural problem of the G.P.zones in Al-Cu alloys. There are distinctive atomic displacements inside and outside the zone. In particular, it is interesting to note that the modulated displacement-waves spread over a relatively wide region surrouding the G.P.zone.抄録全体を表示PDF形式でダウンロード (1037K) -
青木 茂1991 年 55 巻 10 号 p. 1039-1044
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーCu atoms are diffused into Si single crystal samples containing bulk-type stacking faults (SFs), and whole images of the SFs are observed with a transmission electron microscope.
In the case of the samples without Cu diffusion, hexagonal SFs with hexagonal Si oxide precipitates are observed. In the case of the samples with Cu diffusion, SFs having branches and CuSi precipitates on edges or inner parts of the branches are observed. CuSi precipitates grow on the Frank dislocation loop, and interstitial Si atoms are released. such interstitial Si atoms are condensed around the CuSi precipitates, and branches in the ⟨110⟩-direction grow from the SFs.抄録全体を表示PDF形式でダウンロード (2483K) -
野中 勝彦, 田野崎 和夫, 藤田 正義, 千葉 晶彦, 川畑 武, 和泉 修1991 年 55 巻 10 号 p. 1045-1053
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーIn order to clarify the deformation and fracture behavior of a Ti-50 mol%Al alloy, discontinuous compression tests have been performed at room temperature. Surfaces of specimens were observed by optical microscopy and scanning electron microscopy (SEM) to reveal the formation of deformation bands, initiation sites and propagating routes of cracks, and fracturing process at every a few per cent of plastic strain by interrupting the tests.
The compressive plastic strain at crack initiation is 2-3% which is nearly twice as large as the tensile fracture strain reported in the other studies. From the observation of structural changes with cumulative strain the modes of initiation and propagation of cracks are classified. The interfaces of the α2 phase which is present in equiaxed γ phase grains, in grains with a lamellar structure and on grain boundaries, give an initiation site for cracking at the early stage of deformation while the α2 phase itself acts as an obstruction against crack propagation by necking and kinking on crack propagation routes.抄録全体を表示PDF形式でダウンロード (3819K) -
星屋 泰二, 田 昭治, 伊藤 治彦, 高村 三郎, 市橋 芳徳1991 年 55 巻 10 号 p. 1054-1062
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーTransformation characteristics, deformation behaviour and hardness properties of near equi-atomic Ti-Ni shape memory alloys irradiated at 323 K by neutrons to the fast neutron fluence of 8×1023 m−2 have been studied by remote-controlled electrical resistance measurement and tensile and hardness tests.
The MS temperature of a Ti-Ni alloy seemed to decrease to about 100 K by the irradiation and the amount of the decrease in MS was more than 200 K. On the other hand, the TR temperature (the formation temperature of an intermediate phase (R-phase)) shifted to 1∼7 K lower than that of the unirradiated Ti-Ni alloy. The fracture stresses and fracture strains (including elastic strain) at room temperature were in the range of 1300 to 1700 MPa and 6 to 8%, respectively. Unusual elastic behaviour with a recoverable strain of 5% was found in tensile testing.
The atomic replacements formed by neutrons may bring about radiation induced disordering and have an influence on transformation properties and deformation behaviour of those alloys. On the other hand, the restoration of the damage, which follows radiation-induced ordering, can occur on post-irradiation annealings at 523 K for more than 600 s.抄録全体を表示PDF形式でダウンロード (2363K) -
藤井 秀樹, 鈴木 洋夫1991 年 55 巻 10 号 p. 1063-1070
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーEffect of the solutioning conditions on the aging response (precipitation, age hardening) in a β titanium alloy, Ti-15V-3Cr-3Sn-3Al, is examined.
The aging response is strongly affected by the solutioning conditions and closely related to the concentration of quenched-in vacancies, which is a function of the quenching temperatures and the density of the vacancy sinks such as β grain boundaries, dislocations, etc. For example, ω(≤250°C) and α (300∼350°C) precipitations and the age hardening are greatly accelerated in the specimens in which much amount of quenched-in vacancies are included, i. e. specimens quenched from high temperatures and/or with small density of the vacancy sinks. Furthermore, α phase precipitates very homogeneously inside the β grains at the aging temperatures between 300°C and 500°C. However, the precipitation delay and the denuded zone are sometimes observed in the area in which vacancy sinks exist, e. g. in the vicinity of the β grain boundaries or the isolatedly formed twins, or in the area in which dislocations are introduced due to the weak plastic deformation.
In the specimens quenched from lower β region and having smaller β grain size or slightly higher density of dislocations, the delay of the aging response is significant and α phase precipitation is heterogeneous. These phenomena are considered to be caused by a stronger effect of small amount of the excessive vacancies, which is due to the relatively high density of the vacancy sinks and lower quenching temperature, rather than the effect of the β grain boundaries and dislocations as the precipitation sites.抄録全体を表示PDF形式でダウンロード (3200K) -
藤井 秀樹, 鈴木 洋夫1991 年 55 巻 10 号 p. 1071-1077
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーEffect of the quenched-in vacancies on the microstructures during aging in a β titanium alloy, Ti-15V-3Cr-3Sn-3Al, is examined using two materials which are considered to have extremely different concentration of excessive vacancies.
In the material which is considered to have high concentration of quenched-in vacancies, ω (≤250°C) and α (≤300°C) phases precipitate relatively homogeneously in β matrix regardless of dislocations in the early stage of aging, which indicates that the precipitation sites such as complex clusters of solute atoms and vacancies are formed in β matrix in the early stage of aging. Meanwhile, in the material which is considered to have little amount of excessive vacancies, α phase nucleates on the vacancy sinks such as β grain boundaries, dislocations, etc.
The material which is considered to have low concentration of quenched-in vacancies shows a single maximum peak of the age hardening around 400∼500°C. on the other hand, the material which is considered to have high concentration of quenched-in vacancies shows another peak around 300∼350°C in addition to the peak around 400∼500°C. The temperature range of these two peaks agrees to the temperatures at which two types of α morphologies are formed; one is the equiaxed aggregates morphology composed of small particles formed at 300∼350°C, and the other is the lenticular α morphology formed at (400∼500°C), in which some monolithic α plates are included.抄録全体を表示PDF形式でダウンロード (2879K) -
田代 均, 佐藤 洋1991 年 55 巻 10 号 p. 1078-1085
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーMany researches about the effect of alloy elements on the pearlite structure and strengthening by the fiber structure have been made. However, no systematic research on it is available in the literature. Therefore, we have made a systematic research on the pearlite lamellar spacing and the morphology.
(1) The effect of alloy elements on the eutectoid transformation temperature (ACT), pearlite transformation finish time (FTT), pearlite lamellar spacing (LPS) and degree of regularity of pearlite (LPA) depend on each alloy element. The effect cannot be explained by the periodic table reasonably.
(2) Almost an the elements enlarge FTT except Co and Ta.
(3) The effects of the alloy elements on LPS are divided into four groups approximately: \ding172 narrowing, \ding173 widening, \ding174 not changing, and \ding175 widening in the case of a small addition, but narrowing in the case of a large addition.
(4) The higher the transformation temperature, the larger is LPA. Almost all the elements make LPA smaller except Co and Ni.
(5) The C. Zener’s formula holds good in the relationship between the transformation temperature and pearlite lamellar spacing.
(6) The relationship between LPS and pearlite hardness is simillar to the Hall-Petch expression. The elements which dissolve in ferrite cause the solid solution hardening except the above expression.
(7) From the results mentioned above, it is estimated that the combination of the elements of narrowing LPS, the elements of making LPA larger and the elements of strengthening ferrite which do not make FTT larger extremely and do not make LPA smaller greatly is effective for producing higher-strength commercial wires.抄録全体を表示PDF形式でダウンロード (1553K) -
劉 建平, 中佐 啓治郎1991 年 55 巻 10 号 p. 1086-1092
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーA commercially supplied pure-titanium was hydrogen-charged in H2SO4 aqueous solution under the charging current density of 2000 A/m2, and the relation between hydride formation behavior and fatigue strength was investigated.
X-ray diffraction analysis showed the formation of γ-hydride (fcc lattice) on the charged specimens. The volume fraction of hydride increased to take a maximum, once decreased and increased again with increasing hydrogen charging time. The fatigue strength of the specimens charged for tc=7.2 ks, where the hydride volume fraction was maximum, and those charged for tc=14 ks, where almost of all hydride was resolved, were a little larger than the fatigue strength of no-charged specimens. The specimens charged for a longer time than 36 ks showed smaller fatigue strength than no-charged specimens. The reason for the increase or decrease in fatigue life by hydride formation will be attributed to both competitive effects, i. e, one is the generation of residual compressive stress near specimen surface due to the expansion during hydride formation, which win increase the fatigue strength, and another is the fracture of brittle hydride under repeating load, which will decrease the crack nucleation life.抄録全体を表示PDF形式でダウンロード (1485K) -
斉藤 勝男, 乙黒 靖男, 木原 諄二1991 年 55 巻 10 号 p. 1093-1101
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーEffects of the solute concentration and the grain size on the discontinuous deformation of Al-Mg alloys have been studied based on a new idea which differs somewhat from the conventional static strain aging model.
The concentration of Mg and the grain size were varied from 0.2 to 2.5 mass% and from 40 to 500 μm, respectively. Tensile tests were performed in the temperature range from 243 to 473 K. For discussion about effects of the solute concentration and the grain size, only the temperature of 273 K was used.
The exponent M corresponds to so-called (m+β), obtained from the relationship between the critical strain and the strain rate, depends on both of the solute concentration and the grain size. The value of M increases with increasing Mg concentration. The increasing value of M with the solute concentration was discussed based on the assumption that deformation-induced vacancies depend on the plastic strain. The value of M=1.0 was obtained when the Mg concentration was extrapolated to zero. The relation between εc and C0 can be expressed as εcM∝C0−3, this relation cannot be explained using the t2⁄3 rule proposed by Cottrell-Bilby. It can be explained well provided the experimentally accepted t1⁄3 rule is allowed.
The activation energy of discontinuous deformation on the low temperature side was determined as 47.1 and 47.9 kJ/mol for Al-0.5 and 2.5 mass%Mg alloys, respectively.抄録全体を表示PDF形式でダウンロード (1196K) -
小林 信雄, 市之瀬 弘之1991 年 55 巻 10 号 p. 1102-1107
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーIn order to study the corrosion behavior of the α+β alloy, the immersion test and the measurement of the natural potential of a 60/40 brass sheet which was cold-rolled up to 90% total reduction under the condition of 5% reduction per pass, have been carried out in a 3 mass%NaCl aqueous solution, and the residual stress and the rolling texture have been investigated by means of X-ray diffraction. The corrosion rate curve obtained showed a maximum value at 50% reduction, subsequently decreased at 80% total reduction, and then increased slightly at 90% total reduction. The relation between the immersion time and the natural potential resembled the relation between corrosion rate and total reduction as the tendency of the curve was inverted, and the same is true for the relation between the residual stress and total reduction. As the dominant factor of corrosion, the dependence of crystal orientation or the priority solution of the β phase can hardly be considered, and the effect of residual stress is deduced to play the main role. From the microstructure observations of the rolling surface and the longitudinal section, the β phase was stable up to approximately 40% total reduction and the rolling deformation was carried out mainly in the a phase, but at heavy deformations a singular plastic deformation with a activity of shear bands occurred in the β phase, thus contributing to plastic deformation greatly. Consequently, it is deduced that due to such a vigorous activity the inner stresses which were accumulated at a grain or phase boundary are released and there by the residual stress decreases.抄録全体を表示PDF形式でダウンロード (1772K) -
加藤 雅敏, 榊 孝1991 年 55 巻 10 号 p. 1108-1114
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーCr is widely used as an essential alloying element for improvement of corrosion resistance. Metallic Cr has a poor workability in itself and therefore scarcely is used. Recently the high purity Cr sheets have been developed by the improved processing techniques and electrolytic techniques, so that various types of sheets and pipes can be fabricated. It is known that pure Cr and Cr base alloys have not so good corrosion resistance in non-oxidized acid. However, the corrosion behaviour of pure Cr has not yet been completely investigated.
Corrosion behaviours of 99.83%Cr as well as Fe-Cr alloys and Ti were investigated by measuring the polarization curves and corrosion rates in the solutions of various HCI concentrations.
Cr has a large value of active dissolution current in a HCI solution of less than 10% concentration, but the passive current density is very small. And the passivation ability of Cr is higher than the other materials. Cr has much better corrosion resistance in HCl solutions than Ti and the other Fe-Cr alloys. However, with increasing temperature or concentration of HCl, the accelerated active dissolution current and the passive current density increase. On the other hand, the active dissolution currents and passtve currents of the Fe-30Cr alloy and Ti are much larger than those of Cr. Therefore they do not show any passivation ability in all HCI solutions.抄録全体を表示PDF形式でダウンロード (811K) -
梶村 治彦, 山中 和夫1991 年 55 巻 10 号 p. 1115-1122
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーThe repassivation behaviors of newly created surfaces of pure Zr, Zr-15Ti alloy, pure Ti and 25Cr-20Ni-0.25Nb (310Nb) stainless steel were investigated at both passive and transpassive potentials in 17%HNO3 solution by a rapid straining electrode test.
(1) The current density (i) measured by the strain electrode test decayed according to the following formula: i∝exp(−tn) in stage I for first 5 ms after a straining stopped and i∝−t−n (t: time, n: constant) in stage II over a time range from about 5 ms to at least 100 ms.
(2) The ratio of the amount of charge in stage II and stage I (Q2⁄Q1), drastically changed at the transition potential from the passive to transpassive potential. It is thought that both parameters of this potential dependence of Q2⁄Q1 and the amount of Q1 can evaluate whether the localized corrosion occurs or not.
(3) Stress corrosion cracking (SCC) of pure Zr in the high potential region was suppressed by Ti addition due to the formation of a passive film containing Ti.抄録全体を表示PDF形式でダウンロード (959K) -
檀 武弘, 原田 幸明, 村松 祐治1991 年 55 巻 10 号 p. 1123-1129
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーA new method of data processing for the sessile drop technique was developed. The principle of this method is based on the Laplace equation in consideration of hydrostatic pressure in a sessile drop.
This method consists of several procedures as follows.
(1) The contour of the sessile drop was taken into an image processor by a CCD camera.
(2) The principal curvatures and normal angle at many points on this contour are calculated numerically.
(3) The sum of principal curvatures at each point is plotted as a function of the vertical distance from the top of the sessile drop.
(4) The value of surface tension can be determined from the slope of the regession line obtained above.
(5) The value of contact angle can be also obtained from the normal angle at the contact point of both sessile drop and substrate.
The experiment was undertaken on Cu-20 mass%Ni alloy in Ar-7 vol%H2, Ar atmosphere purified by Ti, and Ar atmosphere at 1523-1623 K. The surface tension of this alloy decreased with increasing temperature in the Ar-7 vol%H2 atmosphere. In both the Ar atmosphere purified by Ti and the Ar atmosphere, however, the reverse took place. It can be ascribed to adsorbed oxygen onto the sessile drop surface.
This data processing method can be applied to the real alloy system successfully. It was named “Curvature plotting method”.抄録全体を表示PDF形式でダウンロード (1027K) -
麻生 節夫, 田上 道弘, 後藤 正治, 大城 桂作1991 年 55 巻 10 号 p. 1130-1136
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーThe purpose of this investigation is to determine the liquidus surface phase diagram of the Fe-5%Cr-C-B system and solute concentration of each compounds. Liquidus surface phase diagrams were determined from the thermal analyses and micrographs of 42 kinds of alloys containing 5%Cr, 0∼5.5%C and 0∼4%B. Thermal analysis of each specimen was carried out at a cooling rate of 0.08∼0.25 K·s−1 after melting in an Al2O3 crucible at about 1673 K under argon atmosphere. Chemical composition of each alloy and solute concentration of each phase were analyzed by EPMA.
Six types of phases, i. e., δ, γ, M2B, M3(C, B), M7(C, B)3 and graphite, existed on liquidus surfaces of the Fe-5%Cr-C-B system. In addition, two types of pseudo-binary eutectic reaction, i. e., L→γ+M2B and L→γ+M3(C, B), and two types of peritectic reaction, i. e., L+M2B→+M3(C, B) and L+M7(C, B)3→M3(C, B), occurred on each liquidus surface boundary. The lowest temperature on the liquidus surface (≈1414 K) existed on the pseudo-binary eutectic line in the composition range from 1.5%C, and 1.8%B to 2.0%C, and 1.4%B. The C and B concentrations in the M3 (C, B) and M7 (C, B )3 phases changed in a linear relationship with the alloy composition, while satisfying the stoichiometric relationships. The maximam B solubility of the M3(C, B) phase was about 4.6% and that of the M7(C, B)3 phase was about 2.9%.抄録全体を表示PDF形式でダウンロード (2645K) -
山元 洋, 山本 智実1991 年 55 巻 10 号 p. 1137-1144
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーExperiments were carried out to investigate the magnetic properties of melt-spun Nd-Ce-Fe-Co-B alloys, Ce-Didymium-Fe-Co-B alloys and their bonded magnets. Magnetic properties of the melt-spun Nd-Ce-Fe-Co-B system alloys were deteriorated with the increase of Ce content. A maximum energy product of 134.6 kJ /m3 was obtained for (Nd0.9Ce0.1)11Fe72Co8B9 ribbon prepared at the substrate surface velocity (Vs) of 17.1 m/s. This value was 93.3% of that for Nd11Fe72Co8B9 ribbon (Vs= 17.1 m/s). A maximum energy product of 139.8kJ/m3 was obtained for 26 mass%R-65.4 mass%Fe-7 mass%Co-1.6 mass%B(R=Ce-Didymium) alloy ribbons prepared at Vs=17.1 m/s. Using the 26 mass%R-65.4 mass%Fe-7 mass%Co-1.6 mass%B ribbons prepared at Vs=20.7 m/s, the effect of annealing on the magnetic properties were examined, and the optimum annealing condition was found to be at 650°C for 20 min. Its corresponding value of (BH)max was 135.7 kJ/m3. From the TEM observation, the particle size of these crystallized ribbons was 20-30 nm. A maximum energy product of 90.5 kJ/m3 was achieved with the 26 mass%R-65.4 mass%Fe-7mass%Co-1.6 mass%B bonded magnets made from the optimally prepared ribbons.抄録全体を表示PDF形式でダウンロード (1367K) -
尾上 勝彦, 菊地 真, 田中 熙巳, 岡田 益男, 本間 基文1991 年 55 巻 10 号 p. 1145-1150
発行日: 1991年
公開日: 2008/04/04
ジャーナル フリーThe soft magnetic properties of finely-crystallized Fe-Mo-B-M (additives) ribbons were studied. The microstructures with ultra-fine grains in Fe-Mo-B-M ribbons were obtained by the addition of Cu and Nb into the alloys and subsequent annealing. The effective permeabilities of Fe-Mo-B and Fe-Mo-B-Cu alloys without Nb decreased upon crystallization. Good soft magnetic properties with effective permeabilities of 5000 to 7000 at 1 kHz were obtained by annealing amorphous Fe-Mo-B-Nb and Fe-Mo-B-Cu-Nb alloys above each crystallization temperature. They were composed of bcc Fe crystals with fine grain size of 10 to 20 nm. It was observed that the Nb addition produced nano-scale bcc grains and the Cu addition was effective in homogenizing the nano-crystalline structure.抄録全体を表示PDF形式でダウンロード (1445K)
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