巻号一覧
45 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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田中 志津子1981 年 45 巻 3 号 p. 221-227
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーThe Cu-Pd-Ag dental base alloy of higher Ag contents which contains 15.8 at%Ag was aged isothermally at various temperatures between 573 and 773 K after quenching from the solid solution temperature into iced water. In order to investigate ageing characteristics of the alloy, hardness tests, electrical resistivity measurements, X-ray diffraction analysis and optical microscopic observations were performed.
The maximum hardness given by ageing of the alloy was Hv 460. It was found that the maximum hardness of the alloy was attributed to the discontinuous precipitation of the lamellar structured α2 phase and β phase which contain dispersed fine precipitates. The Johnson-Mehl analysis was applied to the decreasing part of the electrical resistivity curve of the aged alloy and three stages were revealed. They were the first slow stage, the second fast stage and the third slow stage. The time exponent of the second fast stage which corresponds to the discontinuous precipitation was n=1.1∼2.3. Activation energy for the discontinuous precipitation was estimated to be 162∼169 kJ/mol.抄録全体を表示PDF形式でダウンロード (848K) -
和久 芳春, 増本 健, 小倉 次夫1981 年 45 巻 3 号 p. 228-232
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーIn order to study the relation between the rate of fatigue crack propagation and the size of the plastic zone, observations of the plastic zone were made with an Fe-3%Si alloy both on the specimen surface and on the internal section parallel to the surface, and the rate of fatigue crack propagation was measured in a wide range of stress amplitude.
It was found that the relation between the rate of fatigue crack propagation and the stress intensity factor range depended strongly on the stress amplitude. Therefore the rate of fatigue crack propagation could not be expressed as the power function of the stress intensity factor range only. This was attributed to the fact that the size of plastic zone was, in many cases, too large for the conditions of small scale yielding to be satisfied. In the present work, regardless of the scale of yielding, the rate of fatigue crack propagation, da⁄dN, was found to be related to the size of the plastic zone, Zpi, by a power function,
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\ oindentwhere the coefficient D′ and the exponent n, being material’s constants under a fixed experimental condition, were 5.3×10−4 and 2.6, respectively, for the Fe-3%Si alloy.抄録全体を表示PDF形式でダウンロード (388K) -
松山 豊和, 須藤 一1981 年 45 巻 3 号 p. 233-241
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーThe segregation of P and Cr to grain boundaries in Fe-P-Cr ferritic alloys has been studied by Auger electron spectroscopy in relation to the quenching temperature and aging conditions. The results obtained are as follows: (1) The heat of P segregation increases from 14.5 to 71 kJ/mol with increasing bulk Cr concentration from 0 to 5 at%. (2) Equilibrium grain boundary segregation of Cr is slightly increased by alloying P. The heat of Cr segregation is small. (3) Grain boundary concentration of Cr is decreased rapidly (negative segregation) by short time aging, but it is increased by prolonged aging (normal segregation). (4) Alloying Cr suppresses the grain boundary segregation of P during short time aging, but it enhances the segregation after prolonged aging. (5) It is suggested that the “two-dimensional” grain boundary compound phase of high Cr-P is not formed in temper-embrittled low Cr steels.抄録全体を表示PDF形式でダウンロード (637K) -
渡辺 俊六, 津 安英, 高野 勝利, 白石 裕1981 年 45 巻 3 号 p. 242-249
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーDensity of pure iron was measured by the sessile drop method, which was improved to measure the density more accurately than that in the past. Photographs of sample were taken from three directions by three cameras, which were installed at intervals of 2/3 π rad on the horizontal plane. From the image on the film, the volume of samples was calculated by means of an auto-scanning type instrument of length measurement. The average value of the volume calculated from the photographs taken from the three direction was regarded as the volume of the sample, and the density was calculated. The relations between density and temperature were as follows:
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\ oindentwhere σ indicates the standard deviation.
The volume change by the phase transformations from β- to γ-phase, from γ- to δ-phase and from δ- to the liquid phase were −0.94, +0.56 and +3.71% respectively. The error of density measurement estimated was ±0.5%.抄録全体を表示PDF形式でダウンロード (583K) -
草開 清志, 白石 裕1981 年 45 巻 3 号 p. 250-258
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーIn order to obtain the vibrational spectra of molten silicates, infrared emission spectra of molten M2O·xSiO2 (M=Li, Na, K, and x=1 to 4 or 5) were measured in the range of wave numbers between 25000 and 400000 m−1 at temperatures 50 K higher than their liquidus.
Transmission spectra in the molten state were derived from a combination of the two emission spectra which were obtained from the thin and thick layers of samples. The transmission spectra derived from this method in the molten state were compared with that of in the glassy state at room temperature.
The obtained results are summarized as follows:
(1) It is observed that the vibrational frequencies decrease steadily with increasing concentration of alkaline metal oxides in the system, and beyond the 33 mol%Li2O or Na2O and 25 mol%K2O concentrations doublet bands can be observed in the frequency range from 80000 to 100000 m−1 instead of a single band.
(2) The quenching rate from 10−2 to 104 K/s has little influence on the structure of silicate anions in the glassy state, because the obtained spectra were almost the same at any cooling rate.
(3) Though the general pattern of infrared spectra of molten silicates is almost similar to that in the glassy state, it is observed that the vibrational frequencies of molten silicate shift toward the lower frequencies and the band shapes of melt are broader than those of glassy silicates. From the temperature dependence of these changes with the transition from the molten to the glassy state, it may be concluded that the fundamental structure of silicate anions does not differ seriously in both molten and glassy states.抄録全体を表示PDF形式でダウンロード (695K) -
草開 清志, 白石 裕1981 年 45 巻 3 号 p. 259-267
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーIn order to elucidate the behavior of TiO2 in the silicate melt which is well known as amphoteric oxide, infrared emission spectra were measured in the molten state of the Na2O-TiO2-SiO2 system and were compared with the spectra measured in the glassy state including Raman scattering.
The results obtained from the in situ measurement are as follows:
(1) Since the spectrum patterns in molten states are almost similar to those in glassy states, it is concluded that there is no essential difference in the silicate anions in the molten or glassy state.
(2) When TiO2 is added to sodium silicates, two bands appear at 57000 and 33500 m−1. The intensities of these bands increase proportionally with the TiO2 content. They are assigned to the stretching mode (F1u) and the bending mode (F1u) of TiO68− structure belonging to the point group symmetry Oh. Therefore, it is recognized that the Ti4+ ion takes the octahedrally coordinated oxygens in the silicates.
(3) The ratio of the area of the Si-O− (NBO) band to that of the total Si-O− (NBO) and Si-O (BO) bands increases with increasing Na2O or TiO2 content in the melt. Therefore, it is concluded that both TiO2 and Na2O act as strong network modifiers in the silicate melt within the composition range measured.抄録全体を表示PDF形式でダウンロード (706K) -
石崎 哲郎, 武田 隆夫1981 年 45 巻 3 号 p. 268-275
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーHydrogen evolution from iron and steel has been examined by a method of continuous heating up to 1273 K in a vacuum quartz tube attached to a quadrupole mass spectrometer system.
Results obtained are as follows: (1) hydrogen in grain boundaries or dislocations and crystal grains evolves above 673 and 823 K, respectively, and the hydrogen evolution rate changes at the α to γ transformation temperature, (2) the total amount of hydrogen evolved decreases with decreasing solute (C+N) content in iron and steel, and (3) in the steel containing the solute (C+N) and a very small amount of Mn and Si, hydrogen evolves in the paramagnetic β region but does not evolve in the ferromagnetic region.抄録全体を表示PDF形式でダウンロード (608K) -
羽木 秀樹, 林 安徳, 大谷 南海男1981 年 45 巻 3 号 p. 276-282
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーDiffusion of hydrogen has been studied in iron alloys with substitutional elements which act as trapping sites. With the assumption of local equilibrium for hydrogen distribution and the thermal averaging for the jump rate of the hydrogen atom, the apparent diffusion coefficient of hydrogen is derived by considering the interaction energy EB1 between a dissolved hydrogen atom and a substitutional alloying element, and the change ΔE in the energy of the saddle point between the trapping site and the neighboring lattice site.
Diffusion coefficients of hydrogen in annealed poly-crystalline specimens of Fe-(0.50∼3.81 at%)Ni, Fe-(0.39∼4.67 at%)Cr, and Fe-(0.59∼4.63 at%)Co alloys have been measured by the electrochemical permeation method in which alcoholic solutions have been used as electrolytes at temperatures between 230 and 300 K. The experimental permeation curves were analyzed by considering the variation of the hydrogen concentration beneath the cathodic surface during the measurements. The observed temperature dependence of diffusion coefficient of hydrogen can be explained using the following values; ΔE\simeq0, EB1\simeq8.4 kJ/mol for Fe-Cr alloys and ΔE\simeq4.2 kJ/mol, EB1\simeq7.6 kJ/mol for Fe-Ni and Fe-Co alloys.抄録全体を表示PDF形式でダウンロード (573K) -
吉原 一紘, 新居 和嘉1981 年 45 巻 3 号 p. 283-290
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーThe change of the surface composition of low carbon steels was investigated by AES at temperatures between 843 and 1043 K in vacuum.
The surface of low carbon steel was covered with the precipitation layer of graphite below about 970 K which was lower than A1 temperature. Above 970 K, the graphite layer dissolved into the bulk and sulfur segregated on the surface of the steel. When manganese was contained in the low carbon steel, the precipitation temperature of graphite became still lower. When sulfur segregated on the surface of the steel containing manganese, the precipitation rate of graphite became very small even at about 900 K unless sulfur on the surface was removed by argon ion sputtering.
The low carbon steels used in the experiment contained 0.1 mass% of carbon, and carbon precipitated as Fe3C below A1 temperature. Fe3C, however, is unstable thermodynamically, and decomposes to iron and carbon. Carbon grew as graphite on the surface. Both sulfur on the surface and manganese in the bulk stabilized Fe3C so that the decomposition of Fe3C was blocked. Therefore, there existed a temperature range where sulfur segregated on the surface, even when Fe3C precipitated in the bulk. This temperature range was widened when manganese was contained in the low carbon steel.
Both sulfur on the surface and manganese in the bulk also decreased the precipitation rate of graphite on the surface of the low carbon steel.抄録全体を表示PDF形式でダウンロード (581K) -
貞廣 孟史1981 年 45 巻 3 号 p. 291-295
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーEffects of Co content and WC grain size on fracture toughness of WC-Co alloys were investigated. The transverse rupture strength was explained according to the dispersion hardening theory using the fructure toughness values determined experimentally.
The results obtained are as follows.
(1) The fracture toughness value increases with the increase of the Co content and the WC grain size in the alloys and depends on the microstructure parameters, particularly the thickness of Co phase and the contiguity of carbides.
(2) The variation of transverse rupture strength with microstructure parameters shows a maximum at the critical Co content and WC grain size. Above the critical values, the transverse rupture strength follows a dispersion hardening relation, but below those values, it is determined by the fracture toughness and the size of the inherent defect.抄録全体を表示PDF形式でダウンロード (333K) -
榊 孝, 清水 要樹, 崎山 和孝1981 年 45 巻 3 号 p. 296-303
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーThe corrosion behavior of iron-chromium-nickel alloys in 48%NaOH solutions containing NaClO3 and NaCl was investigated mainly by means of potentiodynamic polarization and measurement of the average penetration at temperatures between 140 and 200°C, and the following results were obtained. In 48%NaOH solutions containing NaClO3, anodic dissolution of iron-chromium-nickel alloys in the active state decreased with increasing the nickel and chromium content, and the NaClO3 content. However, the anodic dissolution as NiO22− ion at a low potential of Eh=−0.65 V was unchanged with and without NaClO3 in NaOH solutions. Then, the natural electrode potential of the alloys showed a noble potential with increase in the NaClO3 content. The immersion test showed that the alloys containing low chromium had a comparatively good corrosion resistance by addition of nickel in alkaline solutions containing NaClO3, but high chromium alloys having self-passivation ability decreased the corrosion resistance by addition of Ni in those solutions. The effect of NaClO3 on corrosion of the alloys is caused by its oxidation power. The corrosion behavior of iron-chromium-nickel alloys was invariable in 48%NaOH solutions when the NaCl content was less than 1%.抄録全体を表示PDF形式でダウンロード (439K) -
末吉 秀一, 森崎 秋登, 末永 勝郎, 田中 良平1981 年 45 巻 3 号 p. 304-310
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーTransformation behaviour of super-cooled austenite into ferrite and graphite during iso-thermal treatments of hypo-eutectoid alloy steels containing silicon and nickel or cobalt was investigated by means of hardness testing, optical microscopy and XMA.
The graphite precipitation was found to occur at temperatures below A1 of the iron-graphite system. At higher temperatures in the above range the graphite precipitates directly from austenite, while at lower temperatures austenite transforms into pearlite and then the cementite in the pearlite decomposes into ferrite and graphite. At medium temperatures austenite transforms into graphite and pearlite and then the cementite in the pearlite decomposes into ferrite and graphite.
The TTT relationships of both the graphite and the cementite precipitation showed “C” curve behaviour, and the nose in the curve of the graphite precipitation was found to be at the temperature in which the starting line of the pearlite precipitation intersects with that of the graphite precipitation from austenite.
It was also observed that the graphite nodules formed in the austenite region nucleated heterogeneously on non-metallic inclusions such as Al2O3.抄録全体を表示PDF形式でダウンロード (941K) -
小野 勝敏, 植田 幸富, 森山 徐一郎1981 年 45 巻 3 号 p. 311-316
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーMolybdenum has received considerable attention as engineering materials for heat engine applications. In this study, the possibilities and conditions for winning the pure molybdenum by the carbothermic reduction of MoO2 in vacuum have been examined with regard to the following items: (1) Working conditions and analytical results on the molybdenum obtained by this process. (2) Measurements of solid solubility of oxygen in molybdenum. (3) Vacuum degassing in solid state and evaporation deoxidation in the form of MoO3.
The mechanism of refining of the molybdenum metal by the present method can be characterized by the following steps. Carbon is removed by degassing as CO and the elimination of oxygen takes place in the form of CO and volatile oxides such as MoO3 and MoO2. Both phenomena seem to occur during the refining period in the solid state under vacuum at around 2273 K. Accordingly, the carbon elimination is possible only when an excess of oxygen is present. On the other hand, even after the decrease of carbon, the remaining oxygen can be removed by the oxide evaporation.
With this process the high purity molybdenum in which both carbon and oxygen contents are reduced to a sufficient degree is obtainable by favorable conditions of reduction.抄録全体を表示PDF形式でダウンロード (468K) -
小田原 修, 池内 準1981 年 45 巻 3 号 p. 316-321
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーA new technique for manufacturing metal-ceramic composite materials is proposed and studied by means of a thermit process induced in a centrifugated pipe (“Centrifugal-Thermit Process”). The technique is mainly characterized by the following two effects. (1) A large amount of heat of reaction produced by the thermit process makes the products of reaction immediately melt and form composite with the outer pipe. (2) Gases and impurities existing in the products of reaction are excluded by the centrifugal force.
In the present work, a thermit process of iron oxide and aluminium powders is induced in a steel pipe centrifugated on about 200 G. With the thermit process, aluminium oxide and iron are produced by as 3Fe3O4+8Al=4Al2O3+9Fe+3265 kJ, and the temperature of the system immediately increases more than 3350 K. Therefore, by inducing the thermit process in a centrifugated pipe, the inner surface of the pipe melts and forms a composite with the products of reacton. Since the density of the ceramic (Al2O3) is smaller than that of the metal (Fe), a thick ceramic layer (∼2 mm) is formed inward and the produced metal layer is formed in the intermediate region between the outer steel pipe and the ceramic layer.
The mechanical properties of the composite material produced are measured through hardness, squeezing, and compression-shear tests. The hardness of the ceramic layer is about 15 times as large as that of the metal and steel layers. The strength of the present composite material is evaluated at least as high as that of the steel pipe used in the present work, and the shear strength of the boundary between the ceramic layer and the metal and steel layers is more than 20 MPa.
As a result of the present work, it is confirmed that the centrifugal-thermit process would be a useful method for manufacturing metal-ceramic composite materials with a thick ceramic layer inward.抄録全体を表示PDF形式でダウンロード (728K) -
増本 量, 中山 孝文1981 年 45 巻 3 号 p. 322-326
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーA decrease in magnetostriction and an increase in magnetization with annealing time could be observed in Fe-5.66∼11.22 mass%Al alloys annealed in a magnetic field over the temperature range 573 to 723 K. The maximum permeabilities of the alloys, measured at room temperature when they were cooled down without magnetic field after their time-variations had been terminated, increased as compared with those in the thermally demagnetized state. The relaxation phenomenon was most remarkable in Fe-7.72 mass%Al alloy; its activation energy calculated from the relation between relaxation time and magnetic annealing temperature was about 163 kJ/mol. This value was approximately equivalent to the energy required for interdiffusion of Fe and Al atoms due primarily to the movement of vacancies in the disordered Fe-Al alloys. It seems most probable that the effect of magnetic annealing observed in Fe-Al alloys arises from the rearrangement and stabilization of domains due to the relaxation of internal stress caused by magnetostriction at high temperatures.抄録全体を表示PDF形式でダウンロード (352K) -
小若 正倫, 山中 和夫, 工藤 赳夫1981 年 45 巻 3 号 p. 326-335
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーThe effects of boron on intergranular corrosion, stress corrosion cracking (S.C.C.) and the segregation behavior of boron in Ni-based Alloy 600 were investigated. The results obtained are as follows:
(1) The alloys containing about 7 ppm or more boron were highly susceptible to S.C.C. as annealed but not susceptible after aging at 973 K for 54 ks irrespective of boron contents.
(2) Boron accelerated the grain boundary precipitation of carbides when its content was more than about 11 ppm.
(3) The time-temperature dependence of segregation and precipitation of boron was characterized by C-curve in the temperature range between 673 and 1373 K.
(4) The increase in the susceptibility of intergranular corrosion and S.C.C. corresponded to the precipitation of continuous grain boundary carbides.抄録全体を表示PDF形式でダウンロード (1508K) -
江島 辰彦, 山村 力, 槙 彰, 二階堂 勝1981 年 45 巻 3 号 p. 336-340
発行日: 1981年
公開日: 2008/04/04
ジャーナル フリーIn order to elucidate the relative importance of various factors controlling the diffusion of solute in liquid metals, the impurity diffusion coefficients of fifth period solutes (Ru, Ag, Sn and Sb) in liquid aluminum were measured by the use of the capillary reservoir method at temperatures ranging from 970 to 1200 K.
The values of Di(μ⁄T)1⁄2 (where Di is the impurity diffusion coefficient of solute, μ is the reduced mass of the solvent and solute atoms) increase linearly with the molar volume of the solvent in a similar manner to the values of T1⁄2⁄η (where η is the viscosity of the solvent). The lines showing the relation between Di(μ⁄T)1⁄2 and molar volume were extrapolated to determine the intercept on the axis of molar volume. The intercepts for the fifth period solutes examined agree with one another and also with the line showing the relation between T1⁄2⁄η and molar volume. The values of intercepts agree also with the molar volume of solid aluminum at the freezing point. On the other hand, the slopes of the lines for the solutes differ significantly. These results can be explained in the following way. The impurity atoms are in diffusive motions cooperatively with the solvent atoms and acquire the free volume according to the strength of the interaction between solute and solvent atoms as temperature increases.抄録全体を表示PDF形式でダウンロード (389K)
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