巻号一覧
51 巻, 11 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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荒木 弘安, 下瀬 嘉一, 藤村 全戒1987 年 51 巻 11 号 p. 981-987
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーThe hardness, X-ray diffraction peak broadening parameter, R, and microstructures have been investigated for pure iron and iron alloys containing 3 mass%Cr, Mo or Si when subjected to 10-30% tensile deformation and then isochronal annealing for 3.6 ks. The annealing temperature-hardness curve consists of the slow and rapid softening parts due to recovery and recrystallization, respectively, with increasing annealing temperature. In alloys containing Si or Mo, strain age hardening takes place after annealing at temperature below the recovery stage. In the recovery stage, elongated cells change to several elongated subgrains, which grow and coalesce to a large equiaxis subgrain. The structure changes mentioned above correspond to the stepwise decrease in R value with increasing annealing temperature. The addition of Mo leads to the increase in temperatures required for recovery and recrystallization. The result suggests that Mo atoms with larger atomic size than Fe have strong interaction with vacancies which contribute to recovery and recrystallization. Recrystallization temperature for fine-grained specimens is lower than that for coarsegrained ones, because of the difference in stored energy after the deformation.抄録全体を表示PDF形式でダウンロード (2814K) -
上城 太一, 福富 洋志1987 年 51 巻 11 号 p. 988-993
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーAn interaction enthalpy was evaluated to be −0.098 eV in the temperature range from 773 to 1323 K, assuming that the solubility curve of chromium in copper was a part of the phase diagram of a regular solution. The free energy curved surfaces were depicted to show the free energy barrier to be surmounted in a homogeneous coherent precipitation during aging. Critical unclei corresponding to the theories proposed by Becker, Hobstetter and Borelius can be given by the points on the free energy curved surfaces. The critical size and composition of each uncleus, and the maximum free energy increase in the system, as well as thier temperature dependences were studied. A homogeneous precipitation was discussed in terms of the uncleation triggered by fluctuation of composition.抄録全体を表示PDF形式でダウンロード (956K) -
古川 稔, 美浦 康宏, 根本 実1987 年 51 巻 11 号 p. 994-1002
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーThe relationship between tensile elongation and acoustic emission (AE) detected during compressive deformation of Al-Li and Al-Li-Zr alloys has been investigated for a range of microstructure. For comparison, AE measurements have been carried out for Al-Cu and commercial 7050 alloys. In the polycrystalline binary Al-Li alloys, the most pronounced AE was detected in the under-aged condition during the onset of plastic deformation. The AE increased with increasing Li content, attained a maximum emission at 3-4.5%Li and decreased by further addition over the maximum solid solubility of Li in Al. The strong burst AE was detected in the Al-Li single crystal with a multi-slip orientation. In contrast, the AE in the sample with a single slip orientation was appreciably small. The AE in the binary Al-Li alloys was much greater than those in the Al-Cu and 7050 alloys. The addition of 0.1-0.5%Zr to the polycrystalline Al-Li alloy greatly lowered the AE and improved the ductility appreciably. The proposed sourses of burst AE in the binary Al-Li alloys during the onset of plastic deformation are the formation of coarse slip bands induced by shearing of Ll2-ordered coherent δ′-particles and the intersection of slip bands with each other and with grain boundaries. The intersection of coarse slip bands and weak grain boundaries are considered to be responsible to the loss of ductility in the binary Al-Li alloys. Transmission electron microscope observations of the interaction between deformation induced dislocations and precipitate particles revealed that the dispersion of fine metastable Al3Zr particles changed the mode of dislocation glide through the introduction of the Orowan process.抄録全体を表示PDF形式でダウンロード (2578K) -
田上 耕司, 有井 初志, 甲斐 安直, 松田 日出彦1987 年 51 巻 11 号 p. 1003-1009
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーBending tests are made using bicrystals prepared from the ingots of arc and electron-beam melted pure Mo and its alloys. The character of grain boundaries, the scavenging effect of alloying elements and their effect on the grain boundary fracture stress are mainly investigated. Most of grain boundaries are mixed types having a common rotation axis distributed randomly in the unit stereographic triangle except for the vicinity of (001) pole. It is anticipated that a large amount of oxygen and carbon segregated at the grain boundaries of arc melted pure Mo can fairly be reduced by the addition of titanium and electron-beam melting. Especially, the scavenging effect of titanium on oxygen is successful. The grain boundary strength has a tendency to decrease with increasing atomic misfit of the alloying elements to the solvent in electron-beam melted dilute molybdenum alloys.抄録全体を表示PDF形式でダウンロード (1772K) -
山内 睦文, 藤澤 敏治, 坂尾 弘1987 年 51 巻 11 号 p. 1010-1017
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーThe mean ionic activity coefficients of Ga2(SO4)3 for the binary system Ga2(SO4)3-H2O and the activities of water for the ternary system Ga2(SO4)3-H2SO4-H2O were determined by using the electrochemical and isopiestic methods, respectively, at 298 K. The water activities satisfactorily obey the Zdanovskii’s empirical rule. From the results obtained, the mean ionic activity coefficients of the solutes for the ternary system were calculated by applying the Mckay-Perring method. Furthermore, the applicability of the Meissner’s empirical procedure to estimate the mean ionic activity coefficients of Ga2(SO4)3 and H2SO4 and that of the Robinson-Bower equation to evaluate the water activity to the present ternary solution system were also discussed.抄録全体を表示PDF形式でダウンロード (935K) -
新谷 光二, 長崎 隆吉, 西田 恵三1987 年 51 巻 11 号 p. 1018-1022
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーThe mutual diffusion coefficients of the alumina-chromia system were determined at 1676 K to 1793 K in air. The diffusion couples, which were made of the single crystals of alumina embedded in the powder of chromia, were annealed at each experimental temperature in an electric furnace. The chromia powder was sufficiently densified on the contact interface of alumina. After the diffusion annealing, the concentration-penetration curves along the diffusion direction were determined with the aid of EPMA analysis. The mutual diffusion coefficients were calculated by the Matano-Boltzmann method. The results can be represented by the equation,
(This article is not displayable. Please see full text pdf.)
\ oindentThis formula was close to the previous results obtained by R. P. Nelson. The mutual diffusion coefficients increased exponentially with the increase of chromia-concentration. The activation energy of the mutual diffusion was evaluated as the summation of mobile energy and formation energy of defects.抄録全体を表示PDF形式でダウンロード (692K) -
平井 伸治, 上田 重朋1987 年 51 巻 11 号 p. 1023-1029
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーThe nonporous silicon diffusion coating using the reduction of silicon carbide with titanium has been applied to commercial iron (SPHC) and plain carbon steel (S45C). The results obtained are as follows:
(1) The optimum composition of the pack material was proved to be in a proportion of 18 mass% silicon carbide, 28 mass% titanium, 52 mass% titanium dioxide, and 2 mass% sodium fluoride. When a specimen was treated at 1373 K for 10.8 ks using this pack material, a nonporous silicon treated layer was produced. The SPHC treated layer had the thickness of 380 μm and the Si concentration of 13 mass%.
(2) In the case of SPHC, Fe3Si was identified from the additive layer and α-Fe with Si and Ti in solid solution from the diffusion layer. In the case of S45C, TiSi and Ti5Si3 were identified from the additive layer, TiC from the intermediate layer and α-Fe with Si in solid solution from the diffusion layer.
(3) In this experiment, sodium fluoride acting as an activator and titanium dioxide as a diluent were found to be highly effective in producing a nonporous silicon treated layer having a sufficient concentration of silicon. For example, alumina used as the diluent is reduced by titanium to form Al which suppresses the diffusion of Si.
(4) The cause for the formation of the nonporous silicon treated layer is considered as follows. The Ti which is first diffused in the steel suppresses the diffusion rate of Si which is diffused later and consequently relieves the non-uniform diffusion. Since Ti has a reducing reaction with the silicon carbide powder at the initial stage of the chemical reaction occurring in the pack material, Ti begins to diffuse in the steel while the titanium powder is being consumed for the reduction.抄録全体を表示PDF形式でダウンロード (1157K) -
平井 伸治, 上田 重朋1987 年 51 巻 11 号 p. 1030-1038
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーTitanium diffusion coating using the powder pack process was applied to commercial iron (SPHC) and plain carbon steel (S45C). The effects of the kind of activator and blending ratio of the activator, and the diluent contained in the pack material on the treated layers were investigated.
The results obtained are as follows:
(1) The optimum composition of the pack material was determined from the mass increase of the specimen after diffusion coating. When the specimen was treated at 1373 K for 21.6 ks using a pack material consisting of 33 mass% titanium, 65 mass% alumina, and 2 mass% calcium chloride, the resulting treated layer had a thickness of 40 μm and a Ti concentration of 65 mass%.
(2) When ammonium chloride was used as an activator, a Ti-H compound is formed on the treated layer. Calcium chloride as an activator proved to be the most suitable for obtaining a thick treated layer with a high Ti concentration.
(3) Alumina used as a diluent was reduced with titanium to produce Al. The resulting Al, together with Ti, diffused into steel. This reducing reaction is considered to result from a reduction of the Al activity, which occurs in accordance with the diffusion of the Al into the steel.
(4) Regarding the Al diffusion mechanism in the case of S45C, the diffusion of Al is suppressed by a TiC layer present in the additive layer. However, as the concentration gradient of Al becomes greater, Al diffuses into the basis metal through the TiC layer to form a diffusion layer while the basis metal is decarburized.抄録全体を表示PDF形式でダウンロード (2238K) -
平井 伸治, 上田 重朋1987 年 51 巻 11 号 p. 1039-1044
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーThe titanium diffusion coating using the reduction of titanium dioxide with aluminum has been applied to commercial iron (SPHC) and plain carbon steel (S45C). The results obtained are as follows:
(1) The optimum composition of a pack material is proved to be in a proportion of 75 mass% titanium dioxide, 20 mass% aluminum, and 5 mass% calcium chloride. When a specimen was treated using this pack material at 1373 K, for 10.8 ks, the SPHC treated layer shows the thickness of 250 μm and the Ti concentration of 70 mass%.
(2) The treated layer produced with the addition of calcium chloride as an activator has fewer defects and is thicker than that in the case of using titanium powder as the diffusion source.
(3) As a result of X-ray diffraction analysis of the treated layers, TiO and Fe2Ti were detected in the additive layer for SPHC, whereas TiC and Fe2Ti were detected in the additive layer for S45C. In this case, the diffusion layer is not formed because no diffusion of Al occurs.
(4) The lowest treating temperature necessary to produce the treated layer is found to be near 1073 K.
(5) With SPHC, the activation energy for the growth of the additive layer and the diffusion layer is 69.0 kJ·mol−1 and 65.3 kJ·mol−1 respectively.抄録全体を表示PDF形式でダウンロード (970K) -
中井 弘, 奥畑 孝浩, 岡田 健1987 年 51 巻 11 号 p. 1045-1053
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーThe corrosion of Fe-Ni alloys containing up to 40 mass%Ni at 873-1073 K under mainly 104 Pa SO2 partial pressure was studied by thermogravimetry, X-ray diffraction, SEM, and EPMA. The effect of pre-oxidation on the corrosion of the alloys was also determined.
The addition of Ni caused sigificant deterioration in the corrosion resistance of these alloys. The linear and parabolic rate constants obtained at given SO2 partial pressures increased with the nickel content.
The decreased corrosion resistance was related to the formation of nickel sulfide and the increased transport of nickel ions through the scale.
The pre-oxidation treatment for the alloys yielded a remarkable decrease in corrosion rates and sulfide content in the scales was low during the subsequent corrosion in SO2.抄録全体を表示PDF形式でダウンロード (2722K) -
石川 盛夫, 杉本 克久1987 年 51 巻 11 号 p. 1054-1059
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーSingle, duplex and quadruple layer films having the thickness between 20-300 nm of Al2O3, Cr2O3, TiO2 and their combinations were prepared on an Fe substrate by metalorganic chemical vapor deposition technique. Corrosion protection properties of these films were examined in 3 mass%NaCl, 1 kmol·m−3 H2SO4 and 1 kmol·m−3 NaOH by the measurement of electrochemical activation time. In the case of single layer films, the order of protection ability was Cr2O3>Al2O3>TiO2. The adhesiveness of Cr2O3, however, became poorer with increasing film thickness. Al2O3 films showed good adhesiveness at any film thickness examined. For duplex layer films, the order was Cr2O3 (upper)/Al2O3 (lower)>TiO2 (upper)/Al2O3 (lower)>Al2O3 (upper)/TiO2 (lower). The thickness of 40-50 nm of Cr2O3 layer was necessary to get higher corrosion resistance in the structure Cr2O3 (upper)/Al2O3 (lower). Much higher corrosion resistance was given by quadruple layer films of Cr2O3 (uppermost)/Al2O3/Cr2O3/Al2O3 (lowermost) . The uppermost layer of these films was also needed to be 40-50 nm thickness to get the best resistance. The corrosion resistance of the quadruple films was higher than that of passive films on SUS304 and SUS430 stainless steels.抄録全体を表示PDF形式でダウンロード (922K) -
ヒ 暁, 後藤 和弘1987 年 51 巻 11 号 p. 1060-1068
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーThe oxidation behaviour of four kings of superalloys, which are MAR-M-24LC, X-40, HASTELLOY X and HA188, has been investigated for a period up to 4.2 ks in air at temperatures of 1273 K, 1373 K, 1573 K. The kinetics of oxidation was evaluated through the measurement of the weight gain with time, and the microstructures were observed mainly by means of X-ray diffraction and scanning electron microscopy. All of the oxidation processes obeyed the parabolic rate law. However, in the case of MAR-M-247LC and X-40, spalling of the oxide layers was observed during cooling to room temperature in air after the isothemal oxidation. This could be induced by thermal stress resulteing from the difference in heat expasion coefficients between the oxide formed and the substrates beneath. The observation of the surface oxide showed that their morphologies and structures depended largely on the composion of the superalloys. The oxides mainly formed on the surface of MAR-M-247LC were NiO, Ni (Al, Cr)2O4 and sub-scale of Al2O3 and voids existing in the oxide scale were detected. In the case of X-40, its surface oxides consist predominantly of spinel (Co, Ni) Cr2O4 and corundum Cr2O3, and no void was found, but the scale swelled off from the substrate and have a tendancy toword spalling. While with HASTERLLOY X, the present metallography study revealed the formation of the compact oxide layers with good adherence, which is composed of spinel NiCr2O4 and corundum Cr2O3.抄録全体を表示PDF形式でダウンロード (1624K) -
柴田 政勝, 西 成基1987 年 51 巻 11 号 p. 1069-1075
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーIn the presence of excess amounts of manganese or chromium in Al-4.5%Mg alloys the crystallization of giant intermetallic compounds containg those elements is known to occur. This study was carried out to make clear the effects of iron or titanium on the crystallization region, crystallization temperature, sizes and numbers of giant intermetallic compounds.
(1) Iron or titanium makes the crystallization region of giant intermetallic compounds shift towards low concentration of manganese and chromium:
In the case of iron addition at 933 K.
(This article is not displayable. Please see full text pdf.)
In the case of titanium additions at the same temperature,
(This article is not displayable. Please see full text pdf.)
(2) Crystallization temperature of giant intermetallic compounds rises with iron or titanium content and rises by about 40 K with 0.2 mass% titanium.
(3) Iron or titanium additions resulted in decreasing the size of giant intermetallic compounds and increasing the number of those compounds.抄録全体を表示PDF形式でダウンロード (987K) -
工藤 昌行, 高橋 忠義1987 年 51 巻 11 号 p. 1076-1083
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーAs the molten metal in the upper part of a crucible was stirred, equiaxed crystals occured in the stirred part, settled down, and accumulated succesively on the bottom of the crucible.
In this study, the method was applied to an Al-4 masal%Cu molten alloy in the graphite crucible placed in a furnace having a temperature gradient. When the temperature in the lower part of the melt was lower than that in the upper part of it, chrysanthemum-like crystals and comparatively large liquid areas are observed in the accumulation zone, and the liquid areas may result in the formations of porosity and semimacrosegregation. Inversely, when the temperature in the lower part of the melt was high, the morphology of crystals was changed from chrysanthemum shape to granular one and they were filled in uniformly in the accumulated zone. The volume fractions of solid of the specimens under both thermal conditions, which were quenched at various stages of the stirring, were larger than that estimated by Pfann’s equation, but the measured values agreed approximately with the estimated ones in the cooling process after stirring. Furthermore, a fraction solid, above which the liquid cannot flow through the networks of the equiaxed crystals, is about 0.55.抄録全体を表示PDF形式でダウンロード (2940K) -
市川 洌, 石塚 哲1987 年 51 巻 11 号 p. 1084-1092
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーAn investigation is made on the homogenization of microstructure and improvement of mechanical properties in Cu-Al-Fe alloy containing 9, 9.5 or 10 mass% aluminum and 3 or 4 mass% iron produced by the vacuum rheocasting in which the solidifying alloy is vigorously agitated at high rotation speeds from 60 to 70 rev/s of a stirrer immersed in the alloy.
The torque value in Cu-10%Al-3%Fe alloy solidifying with rotation of stirrer at a speed of 70 s−1 is higher than that at a speed of 60 s−1 under the same cooling condition of 0.06 K/s. Homogeneous microstructures are formed by fragmentation of bamboo-leaf-like crystals with the rotation of stirrer at high speeds during the solidification of the Cu-Al-Fe alloys in the present study. The elongation value in Cu-9.5%Al-3%Fe alloy rheocast at a rotation speed of 60 s−1 is 141% for a strain rate of 0.93×10−4 at 1073 K. The elongation value in Cu-9.5%Al-4%Fe alloy rheocast at 60 s−1 is 172% for a strain rate of 0.93×10−4 s−1 at 1073 K. The elongation value in Cu-10%Al-3%Fe alloy rheocast at 60 s−1 is 147% for a strain rate of 1.85×10−4 s−1 at 1023 K. The elongation value in Cu-10%Al-4%Fe alloy rheocast at 60 s−1 is 294% for a strain rate of 0.93×10−4 s−1 at 1023 K. It is found that the elongation values in the present Cu-Al-Fe alloys rheocast at 60 s−1 are much larger than those in the conventionally cast alloys at elevated temperatures.抄録全体を表示PDF形式でダウンロード (4470K) -
比内 正勝, 沢谷 昭八, 増本 量1987 年 51 巻 11 号 p. 1093-1099
発行日: 1987年
公開日: 2008/04/04
ジャーナル フリーThe internal friction Q−1, and magnetic and mecanical properties were investigated as a function of Cr concentration in Ni-Co-Nb-Cr alloys containing 25, 45 or 65%Co and 3 or 5%Nb when furnace-cooled or water-quenched after heating at 1273 K for 7.2 ks. Measurements of the Q−1 and magnetic properties were carried out by an inverted torsion pendulum method and an automatic recording fluxmeter, and the mechanical properties were studied by using an Instron-type tensile testing machine.
The maximum internal friction against the maximum shear strain-amplitude, Qmax−1, increased with Cr concentration, and the highest values of 59-91×10−3 were obtained for the alloys investigated. In the case of Ni-Co-Nb-Cr alloys with constant 3%Nb and 25, 45 and 65%Co, the Qmax−1 were highest at 3%Cr upon furnace cooling and 1%Cr upon water quenching, respectively. In the case of Ni-Co-Nb-Cr alloys with constant 5%Nb and 25, 45 and 65%Co, the highest values of Qmax−1 were obtained at 1%, 3% and 2%Cr upon furnace cooling and at 1%Cr upon water quenching, respectively.
The coercive force Hc of the alloys decreased with the the increase in Cr concentration. The Hc of the alloys with high values of Qmax−1 increased with the increase in Co concentration; 0.051∼0.053 kA/m at 25%Co, 0.075∼0.11 kA/m at 45%Co and 0.10∼0.13 kA/m at 65%Co.
Both the tensile strength and the yield strength of the alloys increased with increasing Cr concentration, while the elongation remained almost unchanged and showed fairly large values of 40∼60%.抄録全体を表示PDF形式でダウンロード (881K)
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