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76 巻, 5 号
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山本 大, 河合 一輝, 黒田 健介, 市野 良一, 興戸 正純, 関 あずさ2012 年 76 巻 5 号 p. 283-288
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーThe aim of this study was to elucidate the relationship between the surface roughness and osteoconductivity of anodized titanium surfaces. Before anodizing, titanium substrates with different surface roughness were prepared by wet-polishing. These substrates were anodized at various voltages in H3PO4, H2SO4, and NaOH aqueous solutions, and their surface roughness was controlled simultaneously at the micron level. Surface roughness of these coatings was expressed with the arithmetical means (Ra). The osteoconductivity of anodized samples was evaluated by in vivo tests. In in vivo tests, samples were implanted in rats' tibia for 14 d. Anatase type TiO2 films were formed on all of the anodized samples for in vivo tests. It was newly found that TiO2 film with small Ra value exhibited high osteoconductivity than that with high Ra value, especially when Ra value was <0.3 µm. In addition, the osteoconductivity of anodized samples with Ra/µm >0.3 was not improved by anodizing, showing the same low osteoconductivity of as-polished samples. These tendencies were observed for all of the TiO2 films regardless of the type of electrolytes.
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石井 克佳, 筧 幸次, 米本 朋弘2012 年 76 巻 5 号 p. 289-294
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーThe effect of welding on microstructure and mechanical properties of Inconel 718 was investigated. In this study, the specimens welded by TIG (Tungsten Inert Gas) welding were subjected to two kinds of post-weld heat treatment (PWHT): 954℃ solution treatment+aging and 1045℃ solution treatment+aging. In both the solution treatments, two kinds of intermetallic compounds were observed in the interdendritic region of the weld metal, where δ-phase (Ni3Nb) and Laves-phase ((Ni,Cr,Fe)2(Nb,Ti,Al)) were precipitated. The relationship between mechanical properties and microstructures was examined. The tensile strength, elongation and creep rupture time of the weld specimen treated at 954℃ were decreased by TIG welding due to the coalescence of voids formed around Laves particles in the weld metal. Compared with the base metal, the hardness was decreased in the weld metal while it increased in HAZ (Heat Affected Zone). The solution treatment at 1045℃ resulted in dissolution of much more detrimental phases than the solution treatment at 954℃. As a result, the ductility and creep strength of weld specimen treated at 1045℃ were better than those of specimen treated at 954℃.
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山本 厚之, 塚本 雅章, 岡井 大祐2012 年 76 巻 5 号 p. 295-301
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーRecrystallization processes in Al-Mg-Si alloys after cold-rolling at 30 to 95% reduction rates were observed on the same area in specimens during annealing at 673 K. Together with the results reported in the previous studies recrystallization phenomena are summarized for aluminum alloys in 6000 series in which dislocation cells are formed by deformation. Strain induced grain boundary migration is an apparent phenomena, which is caused by growth of dislocation cells formed near prior grain boundaries. When subgrains surrounded by low and high angle boundaries are formed during annealing from dislocation cells, the high angle boundaries migrate with invading the neighboring subgrains, and with remaining the area surrounded by the low angle boundaries. In the area swept by the high angle boundaries, orientation gradient is quite low, less than 1 degree, while in the remained area, orientation gradient is relatively high. Crystallites, which grow into recrystallized grains, are composed of such areas with low and high dislocation densities in the early stage of recrystallization. The area with relatively high dislocation density is invaded by other recrystallized grains and disappears, as a result the area with low dislocation density becomes recrystallized grains surrounded only by high angle boundaries.
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根本 圭一, 粕谷 平和, 菊川 久夫, 小比賀 透2012 年 76 巻 5 号 p. 302-308
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーAdvanced fiber-reinforced laminated plates have been used for structural members in various fields, by virtue of their high specific strength and stiffness. This paper considers, by use of the second variation of the total potential energy, secondary buckling of cross-ply laminated plates with initial deflection under biaxial compression that is simply supported along four edges. The occurrence of secondary buckling is proven analytically, and the effects of various factors, such as initial imperfection, outer lamination angle, number of layers, biaxial compressive load ratio, and postbuckling deflection pattern, are discussed.
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上盛 広大, 兼子 佳久2012 年 76 巻 5 号 p. 309-313
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーA Ni-Cu alloy film with high composition gradient was fabricated by electrodeposition technique. Because the chemical composition of the electrodeposit depends on the applied electrochemical potential in solution containing nickel and copper ions, we could grow the gradient-composition Ni-Cu alloy film by applying a continuously variable potential wave. To obtain a relatively thick film on a substrate, the Ni-Cu layers with high positive and negative gradients were stacked alternately during the electrodeposition. In X-ray diffraction analyses, the gradient-composition film exhibited a very broad peak lying between Ni and Cu peaks, although two diffraction peaks appeared in an electrodeposited Ni/Cu multilayer fabricated using a rectangular potential wave. This broad X-ray peak was consistent with the gradient composition. Vickers hardness of the gradient-composition film was higher than that of the Ni/Cu multilayer with 100 nm layer thickness, by a factor of 1.8. The strength increment in the gradient-composition film could be explained by high-density misfit dislocations which uniformly distributed in the film.
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春名 匠, 清水 貴之, 釜谷 昌幸2012 年 76 巻 5 号 p. 314-320
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーWe have investigated correlation between grain boundary character and susceptibility to sensitization using SUS304 stainless steel foil with coarse-grained structure. The steel foil of 100 µm thickness was heated at 1473 K for several periods, and a heating time of 604.8 ks was selected to prepare the specimen with coarse-grained structure, in which a median of grain size was 229 µm. In the specimen, most of grain boundary planes were parallel to the thickness direction. The specimen was sensitized and subjected to the grain boundary corrosion test in oxalic acid solution. Thereafter, the orientation of each grain and the Σ value of each grain boundary were determined by the electron backscattering diffraction (EBSD) method. The corrosion width at the grain boundary positively corresponding to a degree of sensitization increased with an increase in Σ value, and became stable as the value was more than 19. In addition, the corrosion width at Σ3 grain boundary was scattered. Since most of the grain boundary planes were parallel to the thickness direction of the specimen, orientation to each plane of Σ3 grain boundary was determined from the EBSD results, and the degree of coincidence for atom sites on the Σ3 plane was analyzed. As a result, orientations of the observed Σ3 planes were parallel to the common rotation axes characterizing Σ3 coincidence site lattice (CSL) in space, and the Σ3 grain boundary had three types of planes with different CSL. An area of the unit cell for CSL of the grain boundary plane identified as Σ3 was selected as an index of grain boundary character, and an increase in the area correlated to an increase in the corrosion width.
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松村 吉隆, 村上 秀之, 笠井 一輝, 村上 博道, 野田 和彦2012 年 76 巻 5 号 p. 321-326
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーOxidation resistance and microstructural changes of Pt/Ni+Al two layered coatings were investigated in comparison to those of Pt diffusion coatings. The two layered coatings were successfully prepared by a two-step electroplating process, which involves Pt electroplating followed by Ni+Al-particle composite electroplating. The cross-sectional observations of specimens after the cyclic oxidation test confirmed that the two-layered coatings retarded the formation of voids, suggesting that the top Ni+Al-particle composite layer played a role as the diffusion retarder between the coated layer and the substrate. In addition, the Ni+Al-particle composite coatings preferentially accelerated the formation of the Al2O3 scale on the surface. These results confirmed the beneficial effect of the designed two layered coatings.
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小原 佑記, 佐藤 亮太, 石山 義行, 高島 舞, 大竹 尚登, 葛巻 徹2012 年 76 巻 5 号 p. 327-331
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーTensile testing of a diamond-like carbon (DLC) thin film was carried out by using the originally developed nano-materials testing system (NTS) that consisted by a nano-materials tester and a scanning electron microscope. This experiment is the first step for the formation of graphene by stress-induced transformation of an amorphous carbon film. The study may lead us to new findings of unique properties in a transient state of carbons. Stress-strain curve of the DLC film showed that tensile strength and Young's modulus of the film were approximately 420 MPa and 110 GPa, respectively. To evaluate performance of the NTS, a nano-indentation test was carried out for the same sample. Mechanical properties obtained by NTS were mostly in agreement with that of the indentation test. These experimental results demonstrated that the NTS would be one of the effective testing methods to evaluate the mechanical characteristics of DLC thin films.
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竹元 嘉利, 越智 昌宏, 瀬沼 武秀, 高田 潤, 清水 一郎, 松木 一弘2012 年 76 巻 5 号 p. 332-337
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーThe influence of Al content on the evolution of microstructures and mechanical properties of Ti-xFe-yAl alloys quenched from a β field was investigated via hardness measurements, tensile tests, scanning electron microscopy (SEM) equipped with electron back scattering pattern (EBSP) analyzer, and conventional transmission electron microscopy (TEM). The hardness of Ti-(3-6)Fe-yAl decreased remarkably on addition of 1% Al. In comparison to binary alloys, the maximum hardness decrease was achieved in Ti-4Fe-1Al. The hardness of Ti-4Fe-yAl decreased with increasing Al content up to around 5%, reaching a minimum, then gradually increased. Though all of the Ti-3Fe-yAl alloys showed the martensite structure, Ti-4Fe-yAl showed a structural change of β+ω → β+ω+martensite → β+ω with increasing Al content. Consequently, Ti-4Fe-7Al had the lowest density in the β-type alloys equivalent to that of Ti-6Al-4V. The ratio of reciprocal distance d*0002ω/d*222β on selected-area diffraction (SAD) pattern, which is often used as an indicator of {332}〈113〉 twin formation, was nearly constant up to 5% Al of Ti-4Fe-yAl, but decreased over 6% Al. The tensile tests of both Ti-4Fe-5Al and Ti-4Fe-7Al showed ductility. The deformation behavior of Ti-4Fe-5Al producing strain-induced martensite resembled that of Ti-8Mo. On the other hand, Ti-4Fe-7Al was deformed by a coarse slip of {112}〈111〉 in the same manner as Ti-20Mo, and the SAD pattern analysis revealed that the diffuse reflection of the ω phase in the non-deformed area turned into the spots at the deformation band. It was suggested that Al behaves as a β stabilizer element when added to the lowest β alloy and is available for weight saving, while maintaining the β structure.
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塚本 雅章, 山本 厚之2012 年 76 巻 5 号 p. 338-344
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーTough pitch copper has poor strength at high temperatures and contains much oxygen, which causes difficulty to obtain good joints with diffusion bonding. The authors have reported that roughness on the bonding surfaces and their contact timing were important for diffusion bonding on oxygen free copper. In the present study, solid state diffusion bonding on tough pitch copper was carried out under low pressures with investigating these factors. The specimens were significantly deformed with raising the bonding pressure, while voids at the bonded interface were scarcely changed. Tensile strength of the specimens was increased with decreasing the surface roughness. However, all the specimens fractured at the bonded interfaces and the tensile strengths were reduced in comparison with those of oxygen free copper. Relatively large dimples were partly observed on the fractured surfaces, which would suggest that oxide inclusions existed at the bonded interface. The tensile strength was further improved when contact between bonding surfaces was delayed until the temperature was raised up to bonding condition. The specimens prepared by polishing with emery paper #4000 and buffing fractured at the base metal. The large dimples were not completely observed on the fractured surfaces in such the specimens. The tensile strength was also increased with chemical polishing prior to bonding. Grain boundary migration across the bonded interface remarkably occurred with decreasing the surface roughness and was observed only in the specimens fabricated with the delayed contact procedure. On the other hand, the fracture could occur at the base metal even in the specimens that the grain boundary migration hardly originated.
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小宮 良樹, 清宮 義博2012 年 76 巻 5 号 p. 345-348
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーForming AlN in situ within aluminum in the pressure-less crucible was reported. This AlN formation is caused by AlN combustion synthesis reaction, and the start of the reaction depends on the heating condition. In this paper, the relationship between the formation reaction of AlN and heating condition was surveyed. The heating rate was changed from 873 K to 1273 K. In this temperature zone, AlN forming reaction is expected. By accelerating the heating rate, the formation of AlN was increased. The Al-30 vol%AlN composite can be formed at the condition of 10 K/min by 1273 K. The AlN volume fraction depends on the heating rate around the reaction temperature. Even heating by 973 K, AlN is formed. However AlN volume fraction is independent of the heating rate by this temperature. It shows that exothermic energy of the combustion synthesis reaction is as large as AlN formation accelerates.
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半谷 禎彦, 石井 伸幸, 小山 真司, 宇都宮 登雄, 北原 総一郎2012 年 76 巻 5 号 p. 349-354
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーPorous metal is the multifunctional material with both light weight and high energy absorption properties. In this study, a composite structural material, which consists of ADC12 porous aluminum and dense steel plates, was fabricated using friction stir welding (FSW). ADC12 porous aluminum was fabricated by ADC12 aluminum alloy die castings containing large amount of gases without using blowing agent. It is expected that both fabricating precursor of ADC12 porous aluminum and bonding the precursor to steel can be conducted simultaneously by FSW. Composite material having a porosity of approximately 60% can be obtained at a holding temperature of 948 K and a holding time of 8 min. Fe-Al based intermetallic compound (IMC) layer with the thickness of approximately 20 µm was observed at the interface. It was shown that IMC layer was formed at the foaming (heating) process by diffusion-limited process.
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郡 亜美, 林田 史彦, 篠原 義明, 松村 義人2012 年 76 巻 5 号 p. 355-358
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーPreviously, as a means of expressing the effect of ion bombardment, we proposed an ion bombardment parameter Pi based on the magnitude of the ion momentum and impingement ratio of Ar ions to metal particles. As a result the internal stress of the ferromagnetic films can be controlled by ion bombardment parameter Pi. In this study, molecular mass effects with various sputtering gases such as Ar and Xe on magnetic thin films are quantitatively discussed with ion bombardment parameter Pi. The Ni thin films were prepared by the D.C. magnetron sputtering process. Sputtering gases were using Argon (Ar) and Xenon (Xe). Plasma diagnostics was carried out by single Langmuir-probe during the sputter deposition. The internal stress of the films varies linearly with ion bombardment parameter Pi, regardless of the sputtering gas species. In addition, the magnetostrictive susceptibility of the film is also dependent on Pi. Internal stress and magnetostrictive properties of Ni thin films could be controlled with ion bombardment parameter Pi.
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和田 充弘, 前田 知志, 井上 眞一2012 年 76 巻 5 号 p. 359-363
発行日: 2012年
公開日: 2012/05/12
ジャーナル フリーPlatinum is commonly used as a temperature sensor because of its chemical stability. However, it is often noticed that the sensitivity, defined by temperature coefficient of resistance (TCR), of a thin film deteriorates as the device dimension decreases, compared to the single crystal one. In order to conquer this problem, we intensively studied the relationship between process temperature and the resultant crystal texture such as a grain orientation distribution. Platinum films (400 nm in thickness) were prepared by electro-magneto sputtering on a sapphire single crystal substrate (0001), heated at temperatures between 300℃ and 540℃. The substrate temperature substantially plays a key role to achieve high TCR, and the best value we got was 3900×10−6/℃ at 540℃ (cf. 3920×10−6/℃ for a single crystal), maintaining a high adhesive strength and low surface roughness. This seems to be realized by the fact that the grain boundaries disappeared and the film re-crystallized epitaxially with the substrate at least in some region, say 20 µm wide, investigated by Electron Back-Scattering Diffraction (EBSD).
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