著者
梅川 莊吉
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.18, no.8, pp.449-452, 1954 (Released:2008-04-04)
参考文献数
6

Young’s modulus and its change accompanied by heat-treatment and by cold-working in gold-silver and gold-copper alloys has been measured by lateral vibration method of a cantilever under small amount of stress. The composition dependence of Young’s modulus is monotonous in both alloy systems. Young’s modulus of Cu3Au increases and of CuAu decreases the superlattice formation. The effect of cold work on Young’s modulus is similar for some gold-silver alloys, but it differs considerably with some gold-copper alloys.
著者
辛島 恵美子
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.66, no.12, pp.1236-1245, 2002 (Released:2008-04-24)
参考文献数
27

The Shinkansen Line has experienced no serious car-accidents since its operation start in 1964. Why has the Shinkansen Line been able to keep such a good safety performance? This paper intends to clarify the background and the reasons why those miracles became possible—when, what kinds of risks and what kinds of actions the staff of the Japanese National Railways took in, who participated in the development of the Tokaido Shinkansen railway-axles in 1950s∼1960s as a designer, an investigator, a maintenance engineer, an inspector, or a top executive in technology. I discovered all the staff had been dedicated to their duties and their actions were prudent enough in general. As a result their behaviors have reduced the riskiness of their works objectively. But the most of the staff were not so much sensitive to risk itself as a few technical top executives of JNR. For example when the inspectors first found unexpected micro cracks on the 20% running axles in 1965, the top executives adapted a new management system in 1966 based on those inspections, which contained a systematic long-range R&D plan of high-quality railway-axles as well as an effective risk management for micro cracks.
著者
釘屋 奈都子 永田 和宏 北田 正弘
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.78, no.4, pp.149-158, 2014 (Released:2014-04-01)
参考文献数
14

The manufacturing technique of steel chains used for four Japanese armatures from the end of Muromachi to the Edo period has been investigated. The chains used in Kusazuri (tasset) and two types of Kote (guntlet) were composed of steel rings in round and oval shapes while those used in Kusarikatabira (chainmail) was only round. As for the former ones, round rings were connected by oval rings. The diameter of steel wire of rings was about 1 mm. The steel wire was produced from steel plate with the carbon content of 0.11 to 0.40 mass%. Steel was forge-and-welded twice to make in plate and was cut in a bar. The steel bar was drawn into standardized wires by die with the draft percentage of about 25% and annealed. Drawing of standardized wire followed by annealing was repeated several times to make a wire for armatures. The crystal grains in wires were elongated in axial direction and the aspect ratio of grain in oval rings was larger than that in round rings. A wire was rolled around a stick and cut by chisel to make rings.
著者
杉岡 奈穂子 北田 正弘 西嶋 雅彦
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.77, no.5, pp.185-191, 2013 (Released:2013-05-01)
参考文献数
15

The metallurgical microstructure and mechanical properties of the spear blade manufactured in the Edo period have been investigated. The purpose of this work is to obtain metallographic data of the spear blade, and to clarify the manufacturing technique of the spear blade. The specimen examined was estimated to have been made from the end of the Muromachi period to the Edo period and has the signature of Shinano-no-Kami Minamoto Takamichi. The spear is 31 cm in length and 10.7 mm in maximum width. The metallurgical microstructure and nonmetallic inclusions of the spear blade are observed using an optical microscope. The carbon concentration is determined by chemical analysis. To evaluate the hardness, micro Vickers hardness (Hmv) is used. The microstructure is observed using an optical microscope and a scanning electron microscope (SEM). The concentration of nonmetallic inclusions is obtained by electron dispersive X-ray analysis (EDS).    A cross-sectional image of the spear after chemical etching shows a metal flow pattern formed by deformation, possibly created by hammering. The striped structure of layers of two types of steel containing different carbon contents stacked on top of each other was observed. The bright areas after etching corresponded to the edges and ridges of the spear, which were cooled rapidly, forming the martensite structure. The other dark areas consist of pearlite and α-Fe (ferrite) grains. Optical micrographs of near-edge areas contain pearlite and martensite grains, and core areas contain pearlite and α-Fe grains. The nonmetallic inclusions in the core steel consist of a few metal oxide particles and a glass matrix. There are Fe-Ti oxide grains in the glass matrix, and an unknown oxide particle adhering on the Fe-Ti oxide grain surface was also observed.
著者
花田 修治 渡辺 貞夫 佐藤 敬 和泉 修
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.45, no.12, pp.1279-1284, 1981 (Released:2008-04-04)
参考文献数
30
被引用文献数
5 or 0

Magnetic heads made of Sendust alloy head cores (standard chemical composition: Fe-9.6 wt%Si-5.4 wt%Al) are known to have superior magnetic properties and wear resistance. The cores are usually made by mechanical working, such as slicing and grinding since the alloy is so hard and brittle that it has been believed to be difficult to make head cores by plastic deformation. In the present work, plastic deformability of the alloys was investigated by compressive tests on Sendust single crystals at temperatures between room temperature and 1173 K and various strain rates. Main results are summarized as follows.The operative slip systems are {110}〈111〉 and {112}〈111〉 depending on compressive axis. Therefore, the von Mises criterion for a polycrystalline material to deform plastically by slip within grains is satisfied, indicating that the brittleness of Sendust alloys cannot be explained by the number of independent slip modes available. At room temperature the stress-strain curve exhibits three stages in a similar manner to Fe3Al and Fe3Si with DO3 structure.Above the temperature where yield stress decreases abruptly, the steady state deformation takes place. Under the condition of the steady state deformation, the strain rate is represented by the relationship of \dotε=Bσnexp(−Q⁄kT), where n=4.6 and Q=540 kJ/mol. These results suggest that even a polycrystalline material of Sendust alloy may be deformable under the suitable conditions.
著者
清水 謙一
出版者
公益社団法人 日本金属学会
雑誌
まてりあ (ISSN:13402625)
巻号頁・発行日
vol.37, no.8, pp.655-658, 1998-08-20 (Released:2011-08-11)
参考文献数
27
著者
星 恵理子 北田 正弘
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.67, no.7, pp.336-341, 2003 (Released:2008-04-24)
参考文献数
12

The effects of Cu-containing pigments on degradation of Japanese paper have been investigated. A hand-coloured wood-block print of the late Edo era is used as a naturally aged specimen. To clarify the degradation mechanism, sheets of modern Japanese paper painted with powdered malachite are aged in an environment of 353.15 K(80°C), 65%RH. Pigments are examined with XRD. Degradation of the paper is examined with a three-dimensional fluorescence spectrometer. Cu content in the specimen is measured by ICP-AES and EDS. The Cu concentrations of the cross-sections of naturally aged specimen decrease with increasing depth. In addition, the Cu concentrations at the same depth of the artificially aged paper increase with aging. These results show that the Cu species diffuse from the right to the wrong side of the paper. Although the green pigment of wood-block print contains Cu species and As species, only the Cu species has been detected in the fiber of the degraded part of the paper. The degree of degradation of the accelerated sample painted with malachite becomes higher than that of the unpainted sample. Therefore Cu is the main species that participates in the degradation of paper. The fluorescence intensity of the papers painted with malachite decreased with increasing aging time. This result shows that diffused Cu ions make impurity levels in the band gap of cellulose.
著者
加藤 雅治
出版者
公益社団法人 日本金属学会
雑誌
まてりあ (ISSN:13402625)
巻号頁・発行日
vol.47, no.5, pp.256-261, 2008-05-01 (Released:2011-08-11)
参考文献数
7
被引用文献数
1 or 0
著者
松井 光彦
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.64, no.5, pp.403-406, 2000 (Released:2008-04-24)
参考文献数
7

Recently sodium ionic conductors such as NASICON (Na3Zr2Si2PO12) have been used as the solid electrolyte for EMF(electromotive force) type CO2 sensors. However, it has been hard to obtain a sufficiently high quality in this type of sensor, partly due to the low humidity-resistance of NASICON and partly because of its poor initial response of EMF to CO2 pressure.For the purpose of improving the humidity-resistance and the initial response of EMF of the solid electrolyte CO2 sensors, Li2TiSiO5 is employed as the sensing material instead of NASICON. It is composed of the following electrochemical cell:(This article is not displayable. Please see full text pdf.) The electrochemical reaction is in good agreement with the Nernst equation, and reacted electron is calculated as 2.04. The sensor fabricated with Li2TiSiO5 shows good linearity when it is exposed to an atmosphere of 90% relative humidity at 60°C. The initial 90% response of EMF is steadied within 4 min. These experimental results make it possible to use the sensor in the environments.
著者
土屋 正行 泉山 昌夫 今井 勇之進
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.29, no.4, pp.427-433, 1965 (Released:2008-04-04)
参考文献数
24
被引用文献数
2 or 0

The investigation on the transformation of austenite to martensite based on the statistical thermodynamics was carried out using the iron-nitrogen binary alloys containing about 1.8 to 2.8 weight per cent nitrogen. The result of this treatment was compared with that of the iron-carbon binary alloys. The Ms point which was determined microscopically by the Greninger and Troiano method descends with the increase of the nitrogen content and attains room temperature at about 2.2 weight per cent nitrogen showing a complete austenitic structure. Ms points of the iron-nitrogen and iron-carbon alloys containing the same atomic percentage agreed with each other. The T0γ−α′ temperature (ΔFγ→α′=0) of the iron-nitrogen alloy fell nearly parallel to the change in the Ms point with increase of the nitrogen content. On the other hand, the driving force necessary for initiating the martensite transformation increased with increase of the nitrogen content. The effect of carbon on the thermodynamic properties of martensite transformation agreed with the effect of nitrogen. Stabilities of martensites and supersaturated ferrites of the nitrogen- and the carbon-iron alloys were also discussed.
著者
新里 秀平 譯田 真人 尾方 成信
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
(Released:2016-01-22)
参考文献数
25

It is well known that the mechanical strength of iron is significantly changed by alloying. However, atomistic origin and underlying mechanism are still unclear. Since the strength change with respect to solute concentration is very sensitive and highly non-linear, the way of empirical prediction may contribute little to designing the mechanical strength by alloying. In this study, we theoretically construct a model which predicts temperature, strain rate, and solute concentration dependencies on critical resolved shear stress (CRSS) and yield stress of BCC iron alloys with dilute substitutional solutes based on atomistic analysis of the dislocation-solute atom interaction. In the coarse-grained BCC polycrystalline metals, the mechanical strength and deformation are dominated by screw dislocation motion consisting of kink nucleation and migration processes. Thus, our model is based on atomistically computed activation free energies for kink nucleation and migration of screw dislocation. We eventually apply our model to Fe-Si dilute alloy system as a representative example of BCC dilute alloys, and the theoretically predicted CRSS by our model is compared with an experimental one.
著者
吉田 浩一 大中 逸雄
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.61, no.4, pp.342-349, 1997 (Released:2008-04-04)
参考文献数
20

An algorithm has been developed for simulating the solidification in copper billet continuous casting based on the direct finite difference method by assuming a flow field in the melt. The simulation model considers the temperature dependent thermo-physical properties, convection heat transfer due to the movement of liquid and solid phases, latent heat of solidification and heat transfer among carbon and copper molds, billet and cooling water. The simulation results were compared with a measured sump shape, cooling curves and dendrite-arm-spacing (DAS). The sump shape was estimated from the solidification structure obtained by adding molten Sn during casting. An experimentally determined relationship between DAS and cooling rate was used in the estimation of the DAS distribution in the billet. The comparison between calculated and measured results showed a good agreement and it was found that neglecting the heat transfer into the casting direction results in a maximum error of 16.4%. It was also found that a more accurate estimation of the thickness of the solidified layer and temperature near meniscus requires more accurate information on the velocity field.
著者
國貞 雄治 坂口 紀史
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.80, no.9, pp.570-574, 2016 (Released:2016-08-25)
参考文献数
24

We have investigated trapping effects of monoatomic vacancies Vmono and alloy atoms on hydrogen diffusion at Al(111) surfaces. We performed first-principles calculations based on density functional theory with generalized gradient approximation in order to obtain the hydrogen adsorption energies in the vicinity of monoatomic vacancies and alloy atoms in Al(111) subsurfaces. We considered Si, Cr, Mn, Fe, Cu, Ge, and Zn as alloy atoms. We substituted one Al atom with one monoatomic vacancy or alloy atom, which corresponds to Al0.95X0.05(111) (X=Si, Cr, Mn, Fe, Cu, Ge, Zn, Vmono) surfaces. We found that all of monoatomic vacancies and alloy atoms increase adsorption energies. We also clarified that hydrogen atoms make strong covalent bonds in Cr, Mn, Fe-alloyed Al(111) subsurfaces, while they make only weak ionic bonds in pure and Si, Cu, Ge, Zn-alloyed Al(111) subsurfaces.