巻号一覧
46 巻, 5 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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山田 益男, 太田 陸奥雄, 榊原 精1982 年 46 巻 5 号 p. 459-465
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーA series of small-angle X-ray scattering photographs with monochromated and point focussed copper Kα1 radiation was taken of a single crystal of an Al-4 mass%Cu alloy at the as-quenched state from 823 K and at successive stages of ageing at 313 K. The crystal was so oriented that the incident direction of the radiation was along [001] axis, and was cooled with liquid nitrogen during the exposure.
The pattern of the as-quenched state was homogeneous, but each of the patterns of the aged states consisted of streaks along [100] and [010] directions and a quasi-ring around the trace of the incident beam on the film (even at the shortest ageing time, 16 s). The most intense regions were found in [100], [010], [\bar100] and [0\bar10] directions on the ring. With the progress of the ageing the streaks and the ring became more intense and narrower.
The results can be interpreted from points of view of the formation of the G.P. zones parallel to {100} planes ab initio, the effect of the inter-particle interference on scattering of X-rays, and the growth of the G.P. zones with the ageing. Guinier radius of the G.P. zones at each stage can be obtained from intensity change along [110], and the values are reasonably consistent with those obtained from the cross section of the streak. The presence of multilayer zones, besides the one-layer ones, is suggested from the humps found on several intensity curves along [100] at later stages.抄録全体を表示PDF形式でダウンロード (617K) -
太田 陸奥雄, 金谷 輝人, 榊原 精, 山田 益男1982 年 46 巻 5 号 p. 466-474
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーAgeing and reversion in an Al-4 mass%Zn alloy under various conditions have been studied mainly by measurements of the electrical resistivity.
(1) When the alloy is quenched from temperatures lower than 823 K and aged at 233 K or when it is quenched from temperatures lower than 723 K and aged at 263 K, the maximum value of resistivity (ρM) is independent of the quenching temperature. When the alloy is quenched from 873 K and aged at 233 K or when it is quenched from a temperature higher than 773 K and aged at 263 K, the resistivity reaches a value a little larger than ρM in the ageing temperature after a relatively short time and does not change since then. This is considered to correspond to substantial cessation of changes in the number and size of G.P. zones.
(2) Results of the isothermal and isochronal annealing experiments are able to be well explained by considering that there exist two species of G.P. zones, G.P. (s) and G.P. (n), differing from each other in the thermal stability and that G.P. (s) zones formed at the initial stage of ageing may change into G.P. (n) zones as the ageing advances. It is considered that the change from G.P. (s) zones to G.P. (n) zones is facilitated with higher vacancy concentration.抄録全体を表示PDF形式でダウンロード (696K) -
妹尾 与志木, 古賀 重信, 友清 芳二, 沖 憲典, 江口 鉄男1982 年 46 巻 5 号 p. 474-479
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーOstwald ripening of Co precipitates in Cu-Co alloys aged at 873 K was investigated by electron microscopic observation. Radii of the individual precipitated particles were measured from their strain contrasts, and the rate of increase of the mean radius and the relative size distribution were obtained. The size distributions of Co precipitates n Cu-Co alloys are sharp and symmetric, and they do not agree with the theoretical predictions by Lifshitz-Slyozov-Wagner (LSW) and Ardell. The distribution becomes somewhat broad for the large mean concentration, or for the large volume fraction of the precipitates of the alloy, in qualitative agreement with Ardell’s theory. The rate of increase of the mean radius is proportional to the cube root of the aging time, and almost independent of the mean concentration of the alloy in contradiction to the prediction by Ardell. With the increase of the aging time, the shape of the distribution changes slowly, implying that the observed coarsening process of Cu-Co alloy is not in a steady state as assumed in LSW and Ardell’s theory.抄録全体を表示PDF形式でダウンロード (517K) -
泰松 斉, 宮武 克己, 金児 紘征, 中谷 文忠1982 年 46 巻 5 号 p. 480-486
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーThree kinds of stabilized zirconia solid electrolytes with 15 mol%MgO, 15 mol%CaO, or 8 mol%Y2O3, were allowed to react at 1573 K with Fe2O3 in air and with FexO in a CO-CO2 mixture (CO/CO2=1). The reaction zone formed at each reaction couple was investigated by metallographic observation and by electron probe microanalyzer survey. The reactivity of reaction couples was different from one another. Results obtained were as follows:
(1) All stabilized zirconia electrolytes examined were attacked with FexO more severely than with Fe2O3. In particular, ZrO2 (8 mol%Y2O3) was drastically attacked with FexO.
(2) In the ZrO2 (15 mol%CaO)/Fe2O3 (or FexO) couples, pores were concentrated and enlarged at the grain boundary of ZrO2 (15 mol%CaO) phase near the reaction interface.
(3) In the ZrO2 (15 mol%CaO)/FexO couple, a trace of an original interface remained in FexO phase, showing that the interface moved with proceeding of reaction.
(4) In the ZrO2 (15 mol%MgO)/Fe2O3 couple, an intermediate phase, as identified to be magnesioferrite (MgFe2O4), was formed in Fe2O3 phase slightly apart from the interface. No intermediate phase was detected in the other reaction couples.
(5) The reactivity of stabilized zirconia with iron oxides can be estimated to a considerable extent on the basis of phase diagrams concerned.抄録全体を表示PDF形式でダウンロード (998K) -
向井 楠宏, 相部 久男, 北島 利雄1982 年 46 巻 5 号 p. 487-494
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーThe isobaric method with an alumina capsule has been developed to measure the activity of manganese in liquid Fe-Mn alloys at a satisfactory equilibrium state. The measurements have been made at 1843 K for NMn=0.09∼0.77. The activity of manganese shows a slight positive deviation from Raoult’s law, and the activity coefficient of manganese, γMn, is expressed by the following equation:
(This article is not displayable. Please see full text pdf.)
\ oindentThe attivity coefficient of manganese, γMn°, and the interaction parameter, εMn(Mn), at infinite dilute solution are 1.45 and −0.74, respectively.
These results were in good agreement with the results of Sanbongi et al. obtained by the electromotive force method and those of Steiler et al. by the transportation method.抄録全体を表示PDF形式でダウンロード (681K) -
吉原 一紘, 新居 和嘉1982 年 46 巻 5 号 p. 494-503
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーSurface compositions of SUS304 and SUS347 stainless steels at high temperatures were observed in vacuum with Auger electron spectroscopy.
Non-metal elements, such as carbon, nitrogen, phosphorus and sulfur, segregated on the surfaces of stainless steels. These segregated non-metal elements were replaced one by one according to their surface activities, and finally the most surface active element, sulfur, remained on the surface. The order of surface activities of non-metal elements, however, could change if metal elements co-segregated with them. In this experiment, it was found that chromium and niobium co-segregated with nitrogen, whereas iron and nickel did with phosphorus. The order of surface activities of non-metal elements on the surfaces of SUS304 and SUS347 was as follows; carbon<nitrogen (chromium)<phosphorus (iron, nickel)<nitrogen (niobium)<sulfur. The co-segregating metal elements are indicated in the parentheses.
The segregation-isotherm has been derived on the supposition of the interaction between segregants. From this equation, the following two phenomena are deduced; (1) the interaction energy between non-metal element and co-segregating metal element changes the surface activity of non-metal element; (2) when the interaction between metal element and non-metal element becomes strong and the interaction among non-metal elements weak, the co-segregation of metal element with non-metal element is more remarkably observed. This coincided with the following experimental results; (1) the surface activity of nitrogen co-segregating with niobium was larger than that with chromium; (2) non-metal elements with weak interaction, such as nitrogen and phosphorus, co-segregated with metal elements, whereas sulfur, with strong interaction, did not.抄録全体を表示PDF形式でダウンロード (748K) -
中村 哲, 辻川 茂男, 久松 敬弘1982 年 46 巻 5 号 p. 503-508
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーEffects of a mechanical notch on initiation and growth of stress corrosion cracks in Type 304 steel were studied using a round notched bar specimen. Notches were circumferential ones which had a constant tip radius of 0.13 mm and various depths. Surface layers of notches introduced by electrodischarge machining had electrochemical characteristics different from those of bulk metal. They were removed by transpassive treatment in 0.5 kmol/m3 H2SO4 solution followed by mechanical polishing. Cracking occurred in the potential range from −0.52 to −0.35 V (SCE) in 0.5 kmol/m3 H2SO4 solution containing 0.5 kmol/m3 NaCl at 298 K. At potentials more noble than −0.40 V cracked surfaces were rugged and consisted of mixed low index planes. At −0.43 V, lower than −0.40 V, cracked surfaces consisted of smooth {111} planes. The threshold stress intensity, KISCC, below which no cracks issued was 4 MPa·m1⁄2 both at −0.37 V and −0.43 V. Variation of notch depth in the range from 1.4 to 0.4 mm had no significant effect on the KISCC values obtained.抄録全体を表示PDF形式でダウンロード (554K) -
湯山 茂徳, 久松 敬弘, 岸 輝雄1982 年 46 巻 5 号 p. 509-517
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーCorrosion fatigue (CF) tests were conducted for sensitized 304 austenitic stainless steel to investigate effects of environments, mechanical conditions, and sensitization on crack growth and AE (Acoustic Emission) behavior. The same experimental method as in the previous work conducted for solution treated specimens was employed. The crack growth rates of sensitized specimens were found to be accelerated in air as compared with those in the solution treated case. Those obtained in transpassive region (+1.1 V) and at corrosion potential (Ecorr) for sensitized specimens were more accelerated, due to superposition of the acceleration by sensitization and environmental effects such as intergranular corrosion, metal dissolution, or hydrogen evolved from cathodic reaction. The AE activity during crack growth of sensitized specimens was much higher than that of solution treated specimens through all the ΔK values in this study. This indicates that AE techniques are very useful to monitor crack growth processes under sensitized condition. SEM observations of the sensitized fracture surfaces revealed that many microcracks were nucleated at grain boundaries perpendicularly to the main crack surfaces at higher ΔK than ∼34 MPa·m1⁄2. These microcracks (separations) were concluded to be the main AE source during the crack growth in air under sensitized condition, since the numbers of the separations were proportional to the detected AE event counts. In addition to separations, intergranular-like cracks were observed on the sensitized fracture surfaces tested in transpassive region. The high AE activity (event count rate) at relatively low ΔK level was ascribed to the nucleation of these intergranular-like cracks which arose from intergranular corrosion and triaxial stress in the crack tip plastic zone. Intergranular-like cracks due to hydrogen and triaxial stress as well as the separations were observed on the sensitized fracture surfaces tested at Ecorr. The AE sources which provided the high AE activity during CF crack growth under sensitized condition were shown to be such microcracking processes as separations and intergranular-like cracks caused by the co-operation of environments (intergranular corrosion or hydrogen), triaxial stress (mechanical conditions), and sensitization.抄録全体を表示PDF形式でダウンロード (1022K) -
大平 貴規, 岸 輝雄1982 年 46 巻 5 号 p. 518-525
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーThe acoustic emission source wave analysis was carried out to examine the dynamic information about the magnitude of energy release and time-scale of fracture events. The response function of specimens and transducer was obtained experimentally by the standard step response due to breaking pencil lead, and using this response function, the source waves were determined in terms of energy release-time functions explicitly through a time-domain deconvolution.
This method was tested by measuring the acoustic waveforms from pop-in crack growth in 7075-T6 aluminum alloy. The lifetime of pop-in deduced was about 0.9-2.8 μs, which indicates the mean velocity of pop-in crack growth to be about 80-900 m·s−1 and the maximum velocity approximately 1500 m·s−1. The energy release obtained by this method corresponded well to that calculated from the linear fracture mechanics.抄録全体を表示PDF形式でダウンロード (659K) -
松島 志延, 清水 義彦1982 年 46 巻 5 号 p. 526-529
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーMost of laboratory tests on stress corrosion cracking of the Ni-base Alloy 600 in oxygenated high temperature water have so far been conducted by using double U-bend specimens. As crackings are developed on the inner portion of the double U-bend specimens, it is very difficult to measure the environmental factors such as pH and dissolved oxygen concentration in crevices.
The slow strain rate technique is therefore introduced in the present study to study the effect of environmental factors on SCC susceptibilities of the Ni-base Alloy 600 in oxygenated water. The factors studied are pH (3 to 11), dissolved oxygen (8 to 35 mass ppm), crevice and temperature of the solutions (523 to 583 K).
Heat-treatments of specimens used in this paper were the solution treatment at 1423 K, and the post heat-treatment at 923 K for 18 ks after the solution treatment. The temperature adopted for the majority of tests was 573 K. The tests were carried out in a one-through type autoclave by using the slow strain rate technique at the strain rate of 6.7×10−7 s−1. Sodium hydroxide or hydrochloric acid was added to control the pH, referring to the room temperature value.
In nutral and alkaline solution, the Ni-base Alloy 600 neither solution-treated nor post heat-treated cracked in any tests made in this paper. In acidic solution, the Ni-base Alloy 600 failed by SCC. The susceptibility to SCC in acidic solution increased with increasing quantity of dissolved oxygen, decreasing pH, and crevice. The maximum cracking susceptibility was observed at the temperature range of 553 to 573 K. The post heat-treated specimens were more susceptible to cracking than the solution-treated ones in acidic solutions. The latter specimens showed a mixture of inter- and transgranular crackings and the former cracked intergranularly. These facts suggest that the cracking mechanism of the Ni-base Alloy 600 in oxygenated high temperature acidic solution is ascribed to dissolution of Cr depleted zones.抄録全体を表示PDF形式でダウンロード (398K) -
坂本 芳一, 川内 光則, 平田 進1982 年 46 巻 5 号 p. 530-537
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーThe hydrogen permeation rate through both annealed and cold rolled Pd foil specimens under the conditions of various cathodic current densities which form the region of co-existence of α-Pd and β-Pd phase hydride was measured at 299±1 K by means of the electrochemical permeation method.
The linear relation of log(t1⁄2·Jt) vs 1⁄t in the permeation transients was valid at the beginning of the permeation process, and the moving rate parameter of the α⁄β phase boundary was estimated by using an αmax value previously known. The results were explained by such a model that the rate-determining step of the permeation is a hydrogen-diffusion process in the remaining α-phase Pd of the matrix, accompanying the α⁄β-Pd phase transformation.
The apparent diffusion coefficient of hydrogen determined from the permeation transient by the theoretical solution of diffusion equation where the specimen is assumed to be a homogeneous medium is equivalent to the true diffusion coefficient in the α-Pd phase, but the apparent hydrogen concentration directly beneath the cathodic surface corresponds to the phase equilibrium hydrogen concentration of α-Pd phase in the α⁄β phase boundary related to the moving rate parameter of the phase boundary.
Additions of H2SeO3 to the electrolyte for cathodic polarization strongly inhibited the discharge step of hydrogen ions for both Pd specimens but scarcely influenced the hydrogen permeation behaviors.抄録全体を表示PDF形式でダウンロード (653K) -
矢野 信三, 諸住 正太郎, 幸田 成康1982 年 46 巻 5 号 p. 538-545
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーTensile tests in the temperature range between 293 and 1773 K and the fractographic examination were carried out on 6×10−4 m thick specimens of Mo-0.3, 0.5, 1 and 2 mass%Ti alloys nitrided in a purified N2 atmosphere of 0.1 MPa at 1573 and 1773 K, by reference to the alloys recrystallized in a vacuum at 1773 K.
The recrystallized Mo-1 mass%Ti alloy showed the serrated yielding in the temperature range between 1173 and 1773 K, which seemed to be attributed to strain aging of interstitial impurity and solute Ti atom pairs.
The Mo-0.3 mass%Ti alloy nitrided at 1573 K, and the Mo-0.5 and 1 mass%Ti alloys nitrided at 1773 K exhibited high yield stresses, 6∼8 times higher than those of un-nitrided alloys, while retaining tensile elongations of 5 to 15 pct. These alloys are strengthened mainly by Orowan’s mechanism. However, an additional strengthening effect in the Mo-0.3 mass%Ti alloy nitrided at 1573 K, probably due to excess nitrogen in the coherent strain field around precipitated particles, was observed. The fracture occurred by dimple rupture in the Mo-0.5 and 1 mass%Ti alloys nitrided at 1773 K, containing non-deformable ribbon-shaped TiN particles, but it took place in a chisel edge type with 100% reduction in area in the Mo-0.3 mass%Ti alloy nitrided at 1573 K, containing small disk-shaped TiN particles deformable by some extension.
The Mo-0.5, 1 and 2 mass%Ti alloys nitrided at 1573 K fractured at anomalously low stresses before macroscopic yielding, independent of test temperature. This embrittlement may be attributed to a high stress concentration at a grain boundary built up by the intense slip band arising from localized and concentrated shearing of very thin disk-shaped particles about 10 nm in diameter precipitated near the surface.抄録全体を表示PDF形式でダウンロード (922K) -
池 偉夫, 岡部 広文, 辻 栄治1982 年 46 巻 5 号 p. 546-550
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーA study has been made on the oxidation behaviour of Fe-10Cr alloys with and without Al addition (0.5 mass%) in wet as well as dry oxygen of the atmospheric pressure at temperatures between 1073 and 1173 K. Aluminum addition has increased the protection above 1173 K, below which an effect apparently reversed has been observed within the limit of the test period, i.e., ∼160 ks (∼45 h). The mass gain of the Fe-Cr alloy has been less in the wet than in the dry atmosphere below 1123 K. The Fe-Cr-Al alloy, on the other hand, has not shown such an anomaly under any condition tested. This contrast is not intrinsic one, because the average thickness of the scale on the Fe-Cr-Al alloy in the wet oxygen has not been more than in the dry condition. The excess mass gain in the wet oxygen has been due to the excess in internal oxidation of Al. Further, in the Fe-Cr-Al alloy, two types of scales have been formed at the same time, i.e., a scale composed of outer (Fe, Cr)2O3 layer and inner layer of Al oxide, and the one composed of the internal oxidation zone of Al oxide particles in addition to the outer (Fe, Cr)2O3 layer. The formation of the inner layer, however, has been largely depressed and the internal oxidation zone has been slightly more developed in the wet oxygen.抄録全体を表示PDF形式でダウンロード (575K) -
塙 健三, 明智 清明, 原 善四郎, 中川 威雄1982 年 46 巻 5 号 p. 551-554
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーThe condition to obtain graphite nodules in sintered or powderforged products of cast iron swarf powder is that the carbon content must be less than the solubility in γ phase at a sintering temperature. This is because if all carbon atoms are dissolved in γ phase, pores in P/M products are spheroidized during sintering and supersaturating carbon atoms precipitate as graphite into spheroidal pores during cooling. The present paper confirms this condition using the swarf machined from nodular graphite cast iron. The swarf is pulverized into powder of around 100 mesh, and the carbon content is decreased by removing the graphite separated from the matrix down to 1.7%C which is excess of the solubility of γ phase. The powder was compacted at 600 MPa, sintered in H2 atmosphere at 1423 K for 30 min, powderforged, post-sintered in the range of 1123∼1423 K for 30 min, and air cooled. The results show that nodular graphite is never obtained irrespective of the nodular morphologies in the parent cast iron or of the presence of Mg when the powder contains carbon more than the solubility in γ phase, and that the tensile strength is lower than the parent metal owing to irregular morphology of the graphite.抄録全体を表示PDF形式でダウンロード (662K) -
大野 篤美, 茂木 徹一, 清水 亨1982 年 46 巻 5 号 p. 554-563
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーTwo series of experiments were carried out to study the mechanism of equiaxed crystal formation induced by electromagnetic stirring in an ingot.
Microscopic observation of the solidification process in a transparent H2O-32 mass%NH4Cl model alloy revealed that no dendrite branch detachment occurred during the columnar dendrite growth from the bottom while being stirred. When free crystals were allowed to exist in the liquid before the start of the stirring, they acted as hammers on the growing dendrite tips during stirring and promoted the multiplication of equiaxed crystals.
Other experiments were performed on 99.8%Al, Al-0.9 mass%Si, and Al-2 mass%Cu alloys using a magnetic field in the range of 9.0×10−3 T to 2.7×10−2 T, and the hot top was used only when heat extraction from the molten surface was prevented.
The equiaxed crystal zone in Al alloy ingots expanded as the intensity of the magnetic field increased. The equiaxed crystal zone was most predominant when the magnetic field was applied before pouring.
It was considered that the formation of equiaxed crystals in Al alloy ingots during electromagnetic stirring most easily occurred in the initial stage of solidification. It was concluded that the most suitable position for the electromagnetic stirrer to produce a large amount of equiaxed crystals was the top of the mold near the molten surface.抄録全体を表示PDF形式でダウンロード (1650K) -
田中 浩, 佐藤 優1982 年 46 巻 5 号 p. 564-569
発行日: 1982年
公開日: 2008/04/04
ジャーナル フリーFor obtaining a tube of high uniformity in wall thickness, the drawing should be done keeping the tube and die axes as well as the drawing direction strictly aligned, as has been mentioned in a previous report. In the present report the phenomena of changes in concentricity occurring when the tubes were deliberately drawn out of alignment have been studied. The following are results obtained.
(1) Even a small angle of inclination between the die axis and the drawing direction on the exit side of a die leads to continuous bending of the tube onto the exit die corner, and the wall thickness increases more at the side where it is bent.
(2) The misalignment between the die bore and the tube axis on the entry side of a die makes the wall thickness increase more at the side with least contact with the die face.
(3) By positive application of (1) and (2), placing the thinner side of a tube, for instance, on the side of greater wall thickening in a die bore, improves the concentricity in small numbers of drawing passes.
(4) Proper combination of small inclination angle with misalignment in sinking seems to improve the wall-thickness uniformity of the tube.抄録全体を表示PDF形式でダウンロード (384K)
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