巻号一覧
52 巻, 6 号
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田頭 孝介, 早川 尚, 大西 正敏1988 年 52 巻 6 号 p. 529-535
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーThe formation and decomposition of Mn-N dipoles in extra low carbon steels have been observed during ageing at several temperatures between 523 K and 623 K by means of measurements of the electrical resistivity and its deviation from Matthiessen’s rule (DMR). The amount of nitrogen atoms which contributed to the precipitation of nitride during ageing by the decomposition of quenched-in Mn-N dipoles, x, and the amount of single nitrogen atoms in solid solution which contributed to the precipitation, y, were calculated from the changes in the electrical resistivity and DMR during ageing. The x was increased with the increase of manganese content, whereas the x+y was almost constant independent of manganese content. It has been found that the value of x⁄x+y increases with the increase of manganese content and is always kept constant for the same manganese content independent of ageing temperatures and ageing time. The binding energy of Mn-N dipoles is calculated to be approximately 4.8×10−20 J for the specimen containing 0.29 mass% manganese. But the binding energy tends to decrease with the increase of manganese content.抄録全体を表示PDF形式でダウンロード (903K) -
渡辺 英雄, 青木 彰伸, 村上 英邦, 室賀 健夫, 吉田 直亮1988 年 52 巻 6 号 p. 536-545
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーInterstitial loop formation and void swelling under electron irradiation have been observed with a HVEM in pure Fe-15Cr-(13-28)Ni and Fe-16Cr-17Ni-(0.024-0.1)P alloys in a temperature range between 293 and 873 K. After irradiations, microchemical changes at the void surfaces, matrices and grain boundaries have been analyzed by EDS.
One of the characteristics of interstitial loop formation in Fe-Cr-Ni alloys, compared with pure metals, is that both size and density of loops increase linearly with irradiation time in an early stage of irradiations. This seems to be due to the temporal steady state of point defect accumulation caused by low efficiency of loop nucleation. From the temperature dependence of the loop density, the effective interstitial migration energy 0.9 eV has been derived. At higher temperatures where vacanies are mobile, vacancy loops and stacking fault tetrahedra are observed as well as voids.
By small amount of phosphorus addition, the interstitial loop density and its temperature dependence, which were not changed when Ni content was changed over the wide range, were drastically increased at the relatively lower temperatures (∼573 K) where the effects of long range migration is negligibly small. This indicates that the addition of phosphorus influences mainly the nucleation of interstitial loops. Moreover, based on the interstitial migration energy of 0.9 eV, the binding energy between vacancy and phosphous was estimated to be 0.5 eV.
On the other hand, at higher temperatures, the peak temperatures for the void swelling and the density of the vacancy loop shifted upward by 100 K. Moreover, solute (Ni) segregation to the void surface and the grain boundary are suppressed by phosphorus addition. Such phenomena are thought to be the result of vacancy-phosphorus interactions.抄録全体を表示PDF形式でダウンロード (2608K) -
三井 和博, 三島 良直, 鈴木 朝夫1988 年 52 巻 6 号 p. 546-552
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーOrdering processes have been investigated for deformed Cu3Au alloys which are in the initially ordered or disordered state. Direct observation of the anti-phase domain (APD) by electron microscopy shows that APD morphology in deformed Cu3Au is irregular, being dissimilar to the maze-like morphology typically observed in this alloy. The APD observed in the alloys which are initially ordered and then deformed is elongated along the ⟨100⟩ direction but changes to maze-like morphology as the APD coarsens upon reordering. Because of the higher concentration of lattice defects such as dislocations and stacking faults, APD growth in the deformed Cu3Au is retarded. However, it is revealed by differential thermal analysis that the kinetics at the early stage of ordering, namely APD nucleation, in the disordered and deformed Cu3Au is essentially the same as that of the ordering process in the thermally disordered alloys.抄録全体を表示PDF形式でダウンロード (2164K) -
安藤 繁, 長島 友孝, 下尾 聰夫, 木村 弘1988 年 52 巻 6 号 p. 553-560
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーThe carbon deposition on nickel, Fe-Ni alloys, Fe-Cr alloys and SUS304 in CO-H2 mixtures at 923 and 1203 K has been studied by means of metallography and thermogravimetry, in order to elucidate the effects of nickel and chromium on the carbon deposition behavior on iron. The same carbons as deposited on iron, laminar carbon or filmy carbon and filamentous carbon, are observed on nickel, but the amount of carbon deposit on nickel is much less than that on iron because nickel works less actively as catalyst than iron. Since the catalytic effect of Fe-Ni alloys reduces with increasing nickel content, nickel in iron depresses the carbon deposition. Chromium retards the carbon deposition more significantly than nickel does because of the formation of stable carbide on the surface in an early stage. But the occurrence of crack on the carbide may result in the local deposition of filamentous carbon. The carbon deposition on SUS304 is further retarded by the reduction of catalytic effect and the formation of stable protective film due to nickel and chromium, respectively.抄録全体を表示PDF形式でダウンロード (2941K) -
山内 睦文, 大槻 一行, 藤澤 敏治, 坂尾 弘1988 年 52 巻 6 号 p. 561-566
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーThe distribution ratio of antimony between Na2CO3-slag and molten copper at temperatures of 1423, 1473, and 1523 K has been measured by using a sampling technique in a pure argon atmosphere, and determined as a function of oxygen pressure of the alloy. On the basis of distribution results, predominant dissolved species of antimony in Na2CO3-slag has been suggested to be pentavalent in the oxygen pressure range of 10−3∼10−1 Pa. Furthermore, the effect of CO2 pressure on the antimony distribution has been estimated with the aid of activity data for Na2O-CO2-Sb2O5 melt. These results are compared with other investigations.抄録全体を表示PDF形式でダウンロード (764K) -
井上 勝利, 中山 大三1988 年 52 巻 6 号 p. 567-571
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーEquilibrium and kinetics of solvent extraction of gallium(III) were studied at 303 K with Kelex 100 in toluene from weakly acidic aqueous nitrate media whose ionic strength was maintained constant at 1 mol/dm3.
From the equilibrium study, it was elucidated that gallium(III) is extracted according to the following stoichiometric relation:
(This article is not displayable. Please see full text pdf.)
The extraction equilibrium constant was evaluated as Ke=1.8×103[−].
The extraction rate was measured using a batch-type glass cell vigorously stirred by a impeller with six blades at a constant rotating speed of 1500 rpm. It was found that the extraction rate was of the first order with respect to both gallium(III) in the aqueous phase and Kelex 100 in the organic phase and to be inversely proportional to the square of the hydrogen ion concentration at low pH and tend to become a constant value with increasing pH at high pH.
Taking account of the physico-chemical properties of Kelex 100 and the stabilities of gallium(III)-hydroxo complexes in the aqueous solution under the present experimental conditions, a heterogeneous interfacial reaction model was inferred to interprete the observed concentration dependencies of the reactant species on the extraction rate.抄録全体を表示PDF形式でダウンロード (633K) -
佐藤 彰, 大沢 嘉昭, 荒金 吾郎1988 年 52 巻 6 号 p. 572-580
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーIt has been considered that products with particular crystal structures, such as unidirectionally solidified columnar grains, a single crystal and in-situ composite eutectic structure, can be manufactured with an upward continuous casting process. In this work, after surveying many upward continuous casting processes reported in the literature, a moldless one was selected. An apparatus for this process was constructed while trial experiments with Al were performed, and the manufacturing conditions of aluminum rod by the apparatus were investigated. The temperature distribution along a cast strand was measured by a thermocouple attached to the tip of dummy bar. The crystal structure and the surface conditions of the cast strand were examined.
The position of the solidification front of the cast strand was confirmed to be located at 10∼25 mm above the surface of molten metal by the temperature measurement. The configuration of the solidification front of the cast strand was determined to be flat or slightly convex from the observation of the growth direction of its columnar grains. It was confirmed that the diameter of the cast strand was determined by the temperature of the molten metal, the intensity of secondary cooling and the velocity of upward withdrawing. The cast strand with plus taper (growing bigger) was obtained at a lower temperature, a higher intensity and a lower velocity. The crystal structure of dummy bar affected that of the cast strand.
The cast strand was composed of columnar crystals solidified unidirectionally. The surface conditions of the cast strand were better at a lower rotation speed of cast strand, a higher temperature of molten metal and a higher velocity of upward withdrawing.抄録全体を表示PDF形式でダウンロード (2496K) -
蒲地 一嘉, 伊藤 亨, 山本 勉, 中村 誠治1988 年 52 巻 6 号 p. 581-587
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーThe discharge spark errosion method using fine wire is widely applied to cut the cemented carbides. When the cemented carbides are machined by the method, the deterioration of the mechanical properties have been observed as failure accidents or scattering of the tools life, but a little systematic studies have been reported. In this work, the deterioration of the mechanical properties of the cemented carbides when they were cut by the method were studied.
The cemented carbides of WC-(5.5∼20) mass%Co alloys were machined by the discharge spark errosion method and the machined surface were examined by X-ray diffraction to identify the formed phases by the thermal effects of the discharge spark, and the residual stresses were measured by the X-ray stress measuring method as well as microscopic observation by SEM.
These results of the experiments were compared with the transverse rupture strength of the cut specimens.
From the results of the experiments, it has been made clear that the causes of the deterioration of the mechanical properties of the cemented carbides cut by the discharge spark errosion method would be based on three factors: (1) the formation of brittle phases of eta carbides owing to shortage of carbon by a thermal effect of discharge spark errosion: (2) the microcrack formation on the cut surface: and (3) the residual stress of tension produced on the cut surface due to the thermal effect. These factors are inevitable under high temperature processing of the discharge spark errosion method, but they can be eliminated by annealing above 1373 K by the annihilation of eta carbides and by stress relief of tension. To eliminate the microcracks, it is required to grind the cut surface for a proper depth corresponding to the depth of the microcracks, depending on the machining conditions and the compositions of the cemented carbides.抄録全体を表示PDF形式でダウンロード (2311K) -
市川 洌, 石塚 哲1988 年 52 巻 6 号 p. 588-594
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーAn investigation was made on the microstructures and tensile properties in Al-Cu, Bi-Sn and Bi-Pb eutectic alloys rheocast with the rotation of a stirrer at a high speed of 70 rev/s. The results are summarized as follows.
(1) It is observed that the microstructure of Al-33 mass%Cu alloy ingot rheocast at a rotation speed of 70 s−1 is a colony structure in which the eutectics with a dense lamellar of two phases are surrounded by those of a coarse lamellar of two phases. This morphology is almost the same as the microstructure of conventionally cast Al-33%Cu alloy ingot.
(2) It is observed that the microstructures of Bi-43 mass%Sn and Bi-44.5 mass%Pb alloy ingots are Chinese script eutectic structures with scattering oval regions in the discontinuous eutectic matrix. The structures of the oval regions are primary solid particles in both alloys, but bithmuth crystals will precipitate in the oval region after the solidification of Bi-44.5%Pb alloy.
(3) The elongation value of Al-33%Cu alloy ingot rheocast at a rotation speed of 70 s−1 is 263% for a strain rate of 9.26×10−4 s−1 at a temperature of 773 K. It is thus recognized that this rheocast Al-Cu eutectic alloy induces superplasticity.
(4) The elongation values of Bi-43%Sn alloy ingot rheocast at a rotation speed of 70 s−1 are 25 to 31% for a strain rate from 0.91×10−4 to 4.63×10−4 at 293 K.
(5) The elongation values of Sn-44.5%Pb alloy ingot rheocast at a rotation speed of 70 s−1 are 31 to 40% for a strain rate of 0.93×10−4 to 4.63×10−4 s−1 at 293 K. The elongation value of the alloy ingot is 75% for a strain rate of 1.85×10−4 s−1 at 323 K.抄録全体を表示PDF形式でダウンロード (3022K) -
越後谷 淳一, 須藤 一1988 年 52 巻 6 号 p. 595-602
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーDirectionally solidified structure of MgO-ZrO2 eutectic with a small amounts of additives (CaO, Y2O3, Al2O3 and SiO2) has been investigated. The oriented microstructure with lamellar and fibrous morphologies has been obtained in the case of CaO and Y2O3 additions, in which the additives can be dissolved in the ZrO2 matrix. On the other hand, the cell boundaries have been developed with a small amount of Al2O3 and SiO2. In the case of SiO2 addition, the precipitation of Mg2SiO4 has been observed at the MgO/ZrO2 interface. It nucleates coherently at the MgO side of the interface in the early stage of precipitation. This results from the small solubility of the additives in MgO.抄録全体を表示PDF形式でダウンロード (3810K) -
長谷川 英雄1988 年 52 巻 6 号 p. 603-608
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーThe Y2O3-doped tetragonal zirconia polycrystal (Y-TZP) ceramics were unidirectionally ground with SiC abrasive paper. The changes of the crystal structure in the surface layer of Y-TZP with grinding and subsequent annealing were examined by X-ray diffraction in order to clarify the possibility of texture formation. The results are summarized as follows:
(1) The tetragonal zirconia phase showed a remarkable preferred orientation by grinding, in addition to the formation of both monoclinic and rhombohedral phases through phase transformation under stress. The preferred orientation of the tetragonal phase consisted of the plane (001) parallel to the grinding surface can be explained in terms of the ferroelastic behavior based on the switching of the crystallographic axis [100]\ ightleftharpoons[001] of the tetragonal phase.
(2) By thermal annealing at temperatures up to 1073 K, both the monoclinic and rhombohedral phases disappeared. The preferred orientation of the tetragonal phase, however, has remained even after annealing at temperatures up to 1473 K.
(3) The formation of (001)[110] grinding texture specified in terms not only of the plane (001) parallel to the grinding surface but also of the direction [110] parallel to the grinding direction was revealed through the X-ray pole figure measurements. The texture formation is estimated to be caused by the peculiarity in the elastic property of the tetragonal zirconia phase.抄録全体を表示PDF形式でダウンロード (1012K) -
Long Than Trong, 西村 隆宣, 逢坂 達吉, 合瀬 路博, 森田 幹郎1988 年 52 巻 6 号 p. 609-615
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーThe mechanical properties and wear resistance of Al2O3 fiber and hybrid of Al2O3 and SiC whisker reinforced AA6061 were investigated.
The elastic modulus of T6 heat treated Al2O3/6061 and Al2O3-SiC/6061 composites can be expressed as
(This article is not displayable. Please see full text pdf.)
\ oindentrespectively. The fiber arrangement coefficient α is found to be 0.7 for Al2O3 and 0.45 for SiC whisker.
The wear resistance of Al2O3/6061 composites is inferior to that of SiC/6061 composites. The addition of small volume fractions of SiC whisker to Al2O3/6061 composites gives rise to remarkable improvement of the wear resistance which is, on the contrary, superior to that of SiC/6061 composistes.抄録全体を表示PDF形式でダウンロード (2420K) -
芦塚 正博, 佐々木 豊重, 古川 満彦1988 年 52 巻 6 号 p. 616-621
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーFatigue behavior of HIPed 3 mol%Y2O3 containing tetragonal zirconia polycrystals (TZP) was studied by measuring the fracture stress σf as a function of stressing rate \dotσ (dynamic fatigue technique) and time to failure tf for applied stresses σ from 969 MPa to 1220 MPa (static fatigue technique). Average grain size was 0.42 μm. Crack growth parameter N obtained from dynamic fatigue was 56.2 for 293 K, 25.0 for 523 K and 17.1 for 723 K. The N value at 523 K obtained from static fatigue was 24.0 and was comparable to that from dynamic fatigue. Fatigue at room temperature was little. However, fatigue at 523 K was remarkable compared to that of normal sintering TZP. Failure time obtained from static fatigue was longer than the time estimated from the results of dynamic fatigue. It was estimated that the fatigue of HIPed TZP at 523 K was remarkable because the fracture stress was near to the critical transformation stress. The fracture surface at 298, 523 and 723 K showed a smooth region (mirror region) near the fracture origin and was followed by a rougher area (mist and hackle region) being spread in a radial manner. The fracture surface feature was similar to the typical fracture surface in many ceramics. The mirror region at 723 K was larger than that at 293 and 523 K. Monoclinic zirconia contents on the fracture surface obtained from dynamic fatigue were 37.4% for 293 K, 36.9% for 523 K and 27.1% for 723 K, and were independent of stressing rate. On the other hand, monoclinic zirconia content on the fracture surface was 41.6%, and was independent of holding time.抄録全体を表示PDF形式でダウンロード (1352K)
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