巻号一覧
79 巻, 10 号
選択された号の論文の8件中1～8を表示しています
- |<
- <
- 1
- >
- >|
論文
-
関 一郎, 永田 和宏, 田辺 潤, 芦野 哲也2015 年 79 巻 10 号 p. 475-484
発行日: 2015年
公開日: 2015/10/01
ジャーナル フリーSolubility of Ca and O in molten Ti-Cu alloys equilibrated with a CaO-MgO-CaCl2 ternary flux in CaO or MgO crucibles at 1473 K was analytically investigated. The Equilibrium constant of deoxidization reaction by dissolved Ca can be determined as follows:
CaO(s)in CaO crucible=Cain Metal+Oin Metal, −3.25=logK, K=(aCa•aO)/(aCaO)
Moreover, from the investigated partial pressure of O around the reaction cell, an equilibrium constant of dissoluble reaction of O in the molten alloys can be determined as follows:
1/2O2=Oin Metal, 16.08=logK, K=[aO in Metal]/(PO21/2)
If it is possible to use an equilibrium constant of calcia formation published as a thermodynamic data book, an equilibrium constant of dissolution reaction of calcium into molten alloys can be determined as follows,
Cain Flux=Cain Metal, −2.29=logK, K=[aCa in Metal]/(aCa in Flux)
The activity of CaO in the CaO-MgO-CaCl2 ternary flux equilibrated with a MgO crucible is determined as 0.76 compared to the normal state (aCaO=1) using a CaO crucible. This is obtained from the difference of the equilibrium constants of CaO formation using CaO and MgO crucibles, as expressed by the relation: logK=logK′+logaCaO.
抄録全体を表示PDF形式でダウンロード (2344K) -
田口 智子, 桐野 文良2015 年 79 巻 10 号 p. 485-490
発行日: 2015年
公開日: 2015/10/01
ジャーナル フリーSilver coins, such as mameitagin, which were used in the Edo period, were composed of a silver and copper alloy. In case the mameitagin casting was performed with low silver concentration, traditional metal works technique called iroage was performed on the coin to elute the copper from the alloy and produce an Ag-rich layer on the surface. In a previous study, we reproduced the iroage treatment on an Ag-Cu alloy using umezu (plum vinegar) as the treatment liquid and clarified that citric acid, malic acid and sodium chloride that are the main constituents of umezu, elute copper in the treatment liquid. In this study, the iroage treatment on Ag-Cu alloys was performed under various conditions to clarify the effect of different treatment conditions. The silver concentration of the Ag-Cu alloy samples used in this study were 75%, 45%, and 15%, and the color, surface structure, and silver concentration before and after treatment were investigated by spectrophotometry, scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS), respectively. First, the iroage treatment was performed by varying the immersion time in the treatment liquid. The results show that the copper elution velocity differed depending on Ag concentration in the samples. The treatment liquid temperature affected the amount of copper eluted. The percentage of umezu in the treatment solution did not affect the elution amount of copper. The iroage treatment was performed several times in the samples, and the EDS analysis showed that Ag concentration widely varied after treatment. The results suggest that the surface conditions of the repeatedly treated samples affected the copper elution.
抄録全体を表示PDF形式でダウンロード (2390K) -
太田 俊平, 村井 一恵, 小茂鳥 潤, 深沢 剣吾, 三阪 佳孝, 川嵜 一博2015 年 79 巻 10 号 p. 491-496
発行日: 2015年
公開日: 2015/10/01
ジャーナル フリーWe developed a new surface treatment system, a vacuum atmospheric-controlled induction heating fine particle peening (AIH-FPP) treatment system. The system is able to shoot fine particles at high speed in a controlled atmosphere with less than 10 ppm of oxygen concentrations. In the treatment, the substrate is heated to higher temperature by high frequency induction heating. In order to investigate the effects of treatment temperature and shot of mixed particles of Chromium (Cr) and high speed steel (AISI M42) on the formation of the surface modified layer, carbon steel was treated by vacuum AIH-FPP treatment using Cr particles and mixed shot particles of Cr and AISI M42 (Cr75, 50 and 25 mass%) at 800℃ and 1000℃ in nitrogen atmosphere. The surface modified layer was characterized by a scanning electron micro scope (SEM) and an energy dispersive X-ray spectrometer (EDX). In the case of the specimen treated with mixed shot particles of Cr and AISI M42 (Cr50 and 25 mass%) at 1000℃, a Cr diffused layer was formed at the surface. This was because the diffusion of Cr was accelerated by higher temperature and using mixed shot particles of Cr and AISI M42. Moreover, we revealed that the increase in flow velocity at the point of FPP nozzle accelerated the transfer of Cr.
抄録全体を表示PDF形式でダウンロード (6895K) -
奥村 真彦, 滝 克彦, 齋藤 泰洋, 松下 洋介, 青木 秀之2015 年 79 巻 10 号 p. 497-503
発行日: 2015年
公開日: 2015/10/01
ジャーナル フリーThe effect of perspective structure on the computed tomography (CT) value histogram of a three-dimensional (3D) X-ray computed tomographic image was investigated. Images of sphere bead packed beds were taken and the histograms were compared with each other. Normal distributions were fitted to histogram peaks to evaluate histogram shapes. Peaks corresponding to air and alumina were observed in histograms of alumina bead packed beds. The difference between mean values of the peaks decreased and peak standard deviations increased with decreasing bead diameter because of a stronger partial volume effect. Because of this effect, the CT value of a boundary voxel is between CT values of materials present in the voxel. Peaks corresponding to air and glass were observed in histograms of glass bead packed beds. The mean value of the air peak in glass bead packed beds was smaller than that observed in alumina bead packed beds because the specific gravity of glass is smaller than that of alumina. For beds packed with both alumina and glass beads, peak positions of each material differed from those obtained for beds packed with either alumina or glass beads. This indicates that the partial volume effect is caused by boundaries between not only air and beads but also alumina and glass beads. Therefore, the shape of CT value's histogram depends on the 3D structure of the bed. This suggests that the three-dimensional structure can be evaluated on the basis of histogram shape.
抄録全体を表示PDF形式でダウンロード (6730K) -
高木 誠, 水流 一平, 岩田 博之, 坂 公恭2015 年 79 巻 10 号 p. 504-510
発行日: 2015年
公開日: 2015/10/01
ジャーナル フリーMicrotribology of silicon single crystals is one of the key technologies from the viewpoint of reliability of practical application to microelectromechanical systems (MEMS). In this study, a silicon single crystal (100) wafer was scratched by a silicon single crystal tip under a very small loading force in an atomic force microscope. The scratched area of the wafer surface was elevated with respect to the original, unscratched surface, forming a terrace. The height of the terrace depended on the number of scratch, but did not depend on the loading force. The terrace was a silicon single crystal which was coherent with the silicon single crystal wafer, in spite of the different crystal orientations between the silicon single crystal wafer and the silicon single crystal tip. The friction force of the scratching was very small and did not depend on the loading force. Based on these results, it was concluded that the contact area between the silicon single crystal wafer and the silicon single crystal tip was molten by heat caused by the friction of scratching. Wear debris was an amorphous SiO2.
抄録全体を表示PDF形式でダウンロード (4635K) -
後藤 育壮, 黒沢 憲吾, 大口 健一, 麻生 節夫, 鈴木 寛之, 林 博之, 塩野谷 純一2015 年 79 巻 10 号 p. 511-517
発行日: 2015年
公開日: 2015/10/01
ジャーナル フリーFactors influencing the tensile deformation behavior of pure copper castings for electrical parts were investigated. Two main types of tensile deformation behaviors were distinguished on the basis of the difference in the rupture elongation. These did not depend on the melting conditions and/or the casting design. For the deformation type with higher rupture elongation, approximately the same tensile strengths were obtained with dimpled ductile fracture surfaces. On the other hand, lower rupture elongation was always obtained for the castings fabricated without deoxidation treatment. For deformations of the lower rupture elongation type, brittle fracture surfaces with the solidification structure containing Cu-Cu2O eutectic phase were observed. Therefore, the presence or absence of the Cu-Cu2O eutectic phase was considered to be the dominant factor influencing the tensile deformation behaviors. These findings indicate that adequate deoxidation treatment is particularly important for the prevention of crack generation during deformation.
抄録全体を表示PDF形式でダウンロード (4597K) -
北村 貴典, 秋山 哲也, 淺田 多2015 年 79 巻 10 号 p. 518-522
発行日: 2015年
公開日: 2015/10/01
ジャーナル フリーThis paper deals with the strengthening of spot-welded lap joints through the formation of a new hardened zone (HAZ). The factors needed for strengthening were determined via a previously proposed equation predicting the strength. Using these factors, the strengthening of spot-welded lap joints was examined. First, in order to increase the hardened zone, the edge of the nugget was heated with a laser. Next, cross-tension tests were conducted by using spot-welded lap joints that were heated by a laser at various distances from the nugget. It was found that the fracture position and the cross-tension strength (CTS) were governed by whichever was higher: the strength outside HAZ or the strength at the nugget's edge. It was also shown that the cross-tension strength could be improved by 10%.
抄録全体を表示PDF形式でダウンロード (3824K) -
秋山 哲也, 北村 貴典, 木戸 稔2015 年 79 巻 10 号 p. 523-527
発行日: 2015年
公開日: 2015/10/01
ジャーナル フリーLaser forming is applied on not only flat but also curved plates to create some valuable shapes on them. This method uses two typical deformations, transverse shrinkage and angular distortion caused by laser heating. Many researchers investigated these deformations caused by conventional heating on flat plates in their needs for a long time. In recent days, laser forming comes up as a new clean method to create curved surfaces by using these deformations due to thermal strains. However, even basic behavior has not yet been clear in case that heating is out on already curved plate with initial curvature radius. In this report, transverse shrinkage and angular distortion are investigated as a function of initial curvature radius of a plate. As a result, the effect of initial curvature on transverse shrinkage was basically very small and slightly affected by in-plane strain distribution. Angular distortion of curved plate shows very different behavior from that of flat plate. Curved plates had a tendency to bend to its convex side even heated on convex or concave surface. This phenomenon typically appeared with large heat input.
抄録全体を表示PDF形式でダウンロード (3377K)
- |<
- <
- 1
- >
- >|