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77 巻, 4 号
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堀川 敬太郎, 佐土原 愛, 小林 秀敏, 日野 実2013 年 77 巻 4 号 p. 115-120
発行日: 2013年
公開日: 2013/04/01
ジャーナル フリーHydrogen induced bending deformation was studied by using elecroless Pd-plated pure aluminum. Thin plate specimens were hydrogen-charged by cathodic polarization on a single side. It was observed that an increase in charge time resulted in the bending deformation of the specimens. It was also shown that bending is nearly relieved following hydrogen gas release from the specimens by heating above 300℃. Repetitious bending behavior was not observed due to a combination of hydrogen absorption and desorption resulting from the damage of the plated surface layer. Thermal desorption analysis revealed that the hydrogen induced bending deformation of the Pd-plated aluminum was brought about by the volume expansion of the Pd layer as a result of hydrogen absorption.
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—その(1) 33%圧延—山本 厚之, 梶浦 拓也, 塚本 雅章, 岡井 大祐2013 年 77 巻 4 号 p. 121-130
発行日: 2013年
公開日: 2013/04/01
ジャーナル フリーCrystal rotation due to cold rolling was investigated on commercial 1050 aluminum. A 3-mm-thick specimen was annealed at 803 K for 3.6 ks. The surface of the specimen was electro-polished and then observed using a scanning electron microscope (SEM)-electron backscatter diffraction (EBSD) system. Cold rolling to about 30% reduction in the same direction, electro-polishing and same-area SEM-EBSD observation were repeated until the accumulated reduction rate was 84%. In the present study, changes in grain orientation after the first pass in the cold-rolling process were analyzed in detail. Two types of grain orientation were observed before cold rolling. About 50% of the grains showed near-cube orientation, {001}〈100〉, and the rest showed orientations corresponding to the typical deformation texture for pure metals. Crystal rotations roughly in the rolling direction were observed for both the groups. When one 〈011〉 direction was close to the rolling direction, rotation occurred in the 〈011〉 direction. When two 〈011〉 directions were near the rolling direction, double slip would occur, causing grain rotation in the resultant direction. In the grains with near-cube orientations, rotations in two or three directions occurred in a single grain, leading to the formation of dislocation cells whose orientations differed from one another. Even in such a case, individual rotation of the cells could be interpreted in terms of the geometry in the 〈011〉 direction and the rolling direction.
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塚本 雅章, 梶浦 拓也, 山本 厚之2013 年 77 巻 4 号 p. 131-138
発行日: 2013年
公開日: 2013/04/01
ジャーナル フリーAchieving good tensile strength and low deformation in the case of diffusion bonding of dissimilar materials is difficult because different materials vary in mechanical properties at high temperatures. In the present study, diffusion bonding of OFC (oxygen-free copper) to austenitic stainless steel SUS304 was carried out under pressures that are suitable for suppressing any deformation of the specimens. The specimens could be bonded above 1073 K, and the bonding time slightly influenced the tensile strength. Convex areas on the bonding surfaces of SUS304 were scarcely deformed, and quite large voids were formed at the bonding interface. The void size decreased with decreasing roughness of the bonding surfaces. However, the specimens polished with emery papers #1000 and #4000 could not be bonded. The tensile strength of the specimens did not change when a nickel film was used as a metallic insert. The fracture occurred at the interface between SUS304 and the nickel film. Bonding could not be realized when the bonding surfaces were not in contact while the temperature increased. Copper and chromium oxide layers exist on the bonding surface of OFC and SUS304, respectively. Bonding was inhibited by the latter layer. The tensile strength was significantly improved when the bonding temperature was raised from 1073 K to 1173 K. Chromium inclusions were observed at the bottom of dimples on the fractured surface, which indicated that the chromium oxide layer cohered at 1173 K. Consequently, the fracture at the base metal of OFC was attained in the specimen obtaining sufficient adhesion between the bonding surfaces. Grain boundaries of the specimen did not migrate across the bonded interface, which suggested that the grain boundary migration was not necessarily required to acquire superior joints.
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山田 類, 吉年 規治, 川崎 亮2013 年 77 巻 4 号 p. 139-146
発行日: 2013年
公開日: 2013/04/01
ジャーナル フリーPreparation of Fe-based and Pd-based metallic glassy particles with a diameter of around 500 μm were investigated. Firstly, we measured the critical cooling rate of Pd42.5Cu30Ni7.5P20 metallic glass and our results showed that its critical cooling rate was about 0.4 K/s. Pd-based metallic glassy spherical particles with fully amorphous structure were successfully prepared by heating the samples on the Al2O3 substrate up to their melting points and cooling under the cooling rate of around 3 K/s. In contrast, [(Fe0.5Co0.5)0.75Si0.05B0.2]96Nb4 metallic glassy particles cannot be prepared by the same process. This seemed to be caused by a reaction between the Fe-based metallic glass and the Al2O3 substrate around its melting point. This result suggested that containerless solidification method is expected to be used to prepare Fe-based metallic glassy particles. We successfully prepared mono-sized spherical particles of [(Fe0.5Co0.5)0.75Si0.05B0.2]96Nb4 metallic glass by Pulsated Orifice Ejection Method (POEM) as an ideal process for Fe-based metallic glasses.
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鈴木 千明, 筧 幸次, 近藤 大介2013 年 77 巻 4 号 p. 147-152
発行日: 2013年
公開日: 2013/04/01
ジャーナル フリーRecently, as the material of turbine discs for the civil airplane, P/M superalloys such as Rene95 and RR1000 have been in practical use. This is because the advantages of P/M superalloys are more pronounced in homogeneous structure, mechanical properties and yield rate than the disadvantage in the cost of the process such as HIP by the advance in technology to produce alloy powders. However, PPB (Prior Particle Boundary) is known to decrease the toughness and ductility of PM alloys. In this study, for getting the superfine grain and high strength, the gas-atomized powder was HIPed at a δ-subsolvus temperature. The relationship between the microstructure including PPB and mechanical properties was investigated using Inconel 718, which is used widely as a heat-resistant alloy for the aerospace and energy industries. It was found that HIP treatment at a δ-subsolvus temperature brought about the superfine grain and the high proof strength, and that the increase of the solution treatment temperature reduced the PPB influence.
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温井 淳太, 西本 明生, 赤松 勝也2013 年 77 巻 4 号 p. 153-158
発行日: 2013年
公開日: 2013/04/01
ジャーナル フリーTo apply carbonized organics to solid-carburizing compounds, a low carbon steel, S15C substrate, was solid-carburized at 1223 K for 18.0 ks in air with various carbonized organics in nitrogen atmosphere. Each organic changed to the black carbonized matter after carbonizing at 723 K, whereas almost organics kept a shape during carbonizing. X-ray diffraction (XRD) results show that Ca5(PO4)3(OH), both KCl and KHCO3, BaCO3 and CaCO3 were identified on the surface of carbonized meat and bone meal which is organic animal products, carbonized potato, pumpkin and eggplant which are organic plant products, commercial solid-carburizing powder and milled egg shell powder, respectively. As a result of cross-sectional morphology, the martensitic structure was clearly observed on the surface region of each solid-carburized S15C sample after quenching. Hardened layer depth of most samples solid-carburized with various carbonized organics were comparable to the sample treated with commercial solid-carburizing powder, or more. These results indicate that the carbonate in solid-carburizing compounds acts as energizer for solid-carburizing process and carbonized organics and milled egg shell powder can also be used as compounds and energizer for solid-carburizing process, respectively.
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家永 裕一, 井上 剣志, 上杉 徳照, 東 健司2013 年 77 巻 4 号 p. 159-164
発行日: 2013年
公開日: 2013/04/01
ジャーナル フリーThe extruded Mg-Zn-Y alloy with long-period stacking ordered (LPSO) structures is known to display increased strength at room temperature as well as at elevated temperature. In order to achieve these attractive properties in cast component, we focused on controlling microstructure of Mg96Zn2Y2 (at%) cast alloy by the addition of Ag. Mg96Zn2Y2 cast alloy is composed of α-Mg phase, LPSO phase and Mg3Zn3Y2 phase, on the other hand, Mg-Zn-Y-Ag cast alloy also had 4th phase by an addition of Ag. By the addition of over 1 at% Ag, the yield strength was significantly increased at room temperature without grain refining. Because Mg-Zn-Y-Ag cast alloy was mainly strengthened with the intermetallic compound, rather than solid solution hardening over 1 at% Ag. Furthermore the yield strength of Mg93Zn2Y2Ag3 cast alloy was 20% higher than that of Mg96Zn2Y2 cast alloy at 473 K.
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