巻号一覧
61 巻, 3 号
選択された号の論文の9件中1～9を表示しています
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加藤 雄大, 室賀 健夫, 岩井 岳夫, 本島 修1997 年 61 巻 3 号 p. 191-198
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーCharacterization of the plastic deformation properties of thin damaged layers produced by heavy ion beam in an MeV energy range is being attempted by mean of a very low load indentation technique. This paper focuses on the development of experimental techniques and special considerations in analyzing the measured data from specimens which possess perpendicularly uneven hardness property. For this purpose, metals and alloys of different classes, namely a model austenitic alloy, pure iron and pure vanadium, were irradiated with metallic ions and subsequently subjected to instrumented indentation tests. The load-displacement property obtained from the experiment was analyzed in various schemes to extract the amount of the net hardening due to ion-irradiation.抄録全体を表示PDF形式でダウンロード (740K) -
白石 春樹1997 年 61 巻 3 号 p. 199-208
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーThe helium embrittlement is analyzed by applying a two-dimensional elastic plastic finite element method based on continuum mechanics. This program was written by the present author and can treat large scale plastic deformation. In this program, triangular mesh elements are used assuming plane stress condition. The Mises yield criterion, the J2 flow theory, and the power workhardening law are assumed. The morphology of grain boundary helium bubbles is approximated by cyclic boundary conditions. The effect of workhardenability and bubble morphology on the conventional stress strain curves is surveyed. The deformation mode is divided into two categories. (1) Grain boundary deformation mode, in which localization of strains near the grain boundary occurs. (2) Grain interior deformation mode, in which deformation near the grain boundary ceases and deformation proceeds in the grain interior. Only in the former case, the reduction of total elongation results in and this is interpreted as helium bubble embrittlement. The reduction of workhardening exponent causes severe helium embrittlement in the case of the strain localization mode near the grain boundary.
The loss of total elongation has been considered to be controlled by the bubble areal fraction on the grain boundary. This is partly true and it is revealed that the bubble density has an essential impact on helium embrittlement. The existence of bubbles on the grain boundary enhances stress multiaxiality near the grain boundary. This results in an increase of the hydrostatic component of stress and a different behavior of deformation near the grain boundary.
In view of the prevention of helium embrittlement, the high workhardenability is essential. The high bubble density is also effective, but attention must be paid to bubble coalescence due to the temperature excursion during transient phenomena.抄録全体を表示PDF形式でダウンロード (1212K) -
細谷 敬三, 杉本 克久1997 年 61 巻 3 号 p. 209-215
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーCorrosion behavior of iron in 0.1 kmol·m−3 LiClO4 methanol-water solutions in the range of water contents up to 100% was investigated by the immersion corrosion test, polarization curve and electrode impedance measurement. The effect of water content on the corrosion rate of iron shows a maximum around the water content of 30% and this tendency is considered to be controlled by an anodic process. The electrode impedance diagrams show capacitive loops irrespective of the water content and the capacitive loops deform as the water content changes. This indicates the passivation reaction process is affected by the water content. The corrosion process in methanol-water solutions is also discussed in comparison with the physicochemical characteristics of the solutions such as ion solvation and hydrogen bond structure. The interaction between the methanol molecule and the water molecule in the solution reaches a maximum around a water content of 30%. This is shown by measurements of conductivity, molar volume and solvation enthalpy. Strengthing of the hydrogen bond structure is considered to cause an increase of the proton activity and suppress the passivation process of iron in the methanol-water solutions.抄録全体を表示PDF形式でダウンロード (596K) -
友田 陽, 飯住 健爾, 岩崎 直樹, 佐藤 英男, 松島 正博1997 年 61 巻 3 号 p. 216-224
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーAnodic polarization curves in 5.0%H2SO4 and 1.0%HCl solutions, pitting potentials in 3.0%NaCl solution and critical pitting temperatures in 6.0%FeCl3 solution were measured in 18Mn-18Cr-0.5N(N5), -0.8N(N8) and -0.07N-0.5C(N0), and several related alloys. Here, chemical compositions of alloys and solutions are all shown in mass%. Anodic polarization curves of N0, N5, and N8 in 5.0%H2SO4 showed the three peaks in current density with a negative loop. The threshold Cr concentration to appear the negative loop is estimated to be about 19% on the basis of assumption of preferential Mn dissolusion, which is slightly lower than 22% in Fe-Cr binary alloys. The increase in N concentration in an alloy causes little influence on the anodic polarization curves in 5.0%H2SO4, but lowers the weight loss of samples dipped in 0.5%H2SO4. The localized corrosion resistances in chloride solutions are markedly enhanced: both of the critical pitting potential and pitting temperature are improved by increasing the N concentration in Fe-Mn-Cr alloys as well as in Fe-Cr-Ni-Mo alloys.抄録全体を表示PDF形式でダウンロード (1000K) -
井藤 幹夫, 真島 一彦, 勝山 茂, 永井 宏1997 年 61 巻 3 号 p. 225-234
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーSm2Fe17Nx powders with magnetic anisotropy have been prepared by mechanical grinding (MG) in NH3 atmosphere using a rotary ball mill. The hydrogen content of Sm2Fe17Nx powders after MG increased rapidly till 72 ks with increasing MG time, and showed the maximum at 72 ks. Beyond 72 ks, it decreased with increasing MG time. On the other hand, the nitrogen content monotonously increased with MG time, and it was kept constant beyond 432 ks. Though the powder after MG for 288 ks absorbed 35000 ppm of nitrogen, the magnetic properties of this powder were deteriorated due to the distortion which was introduced into the powder during MG. The powders were prepared by MG for shorter periods between 18∼144 ks and subsequent nitriding. Their magnetic properties such as remanence and rectangularity of the demagnetization curve were extremely improved. The remanence over 1.0 Wb·m−2 and the maximum energy product of 129 kJ·m−3 (16.1 MGOe) were obtained for the powders prepared by MG for 18 and 36 ks and subsequent nitriding. X-ray diffraction patterns of the powders aligned in the magnetic field showed the growth of the (006) peak. This indicates that these powders have the magnetic anisotropy. It is considered that an increase of MG time deteriorates the magnetic anisotropy due to the pulverization of powders.抄録全体を表示PDF形式でダウンロード (1161K) -
井口 征夫, 鈴木 一弘, 筋田 成子, 西池 氏裕1997 年 61 巻 3 号 p. 235-240
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーIn order to clarify the influence of the pre-treatment on the magnetic properties of TiN-coated silicon steel sheets, various acid treatments on the silicon steel sheets were done prior to the TiN coating by the HCD method.
With chemical polishing prior to TiN coating, the iron loss W17⁄50(W/kg) of the TiN-coated silicon steel sheets was dramatically improved by 0.20-0.24 W/kg. In contrast, with the pre-treatments with 10%H2SO4 and 10%HCl solutions, the improvement of W17⁄50(W/kg) was reduced to 0.1-0.14 W/kg. Also, the improvement of W17⁄50(W/kg) in the pre-treatment with the H2SO4 solution was less than that with the HCl solution.
By the pre-treatments with 10%H2SO4 and 10%HCl solutions, the value of W17⁄50(W/kg) became lower than that of a silicon steel product, but by subsequent TiN coating both We and Wh were improved. However, the improvement of W17⁄50(W/kg) due to the pre-treatment with these acid solutions showed 60-70% of that in the case of chemical polishing.
The thin-film X-ray diffraction in the 111 peak intensity of TiN became weaker in the order of chemical polishing, the 10%HCl solution and the 10%H2SO4 solution, and in the latter case showed 200, 220 and 311 peaks of TiN.抄録全体を表示PDF形式でダウンロード (1094K) -
折橋 正樹, 野田 泰稔, 海部 宏昌, 西田 勲夫1997 年 61 巻 3 号 p. 241-246
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーPbTe single crystals were prepared by the Bridgman method, where either Ag2Te or PbI2 was doped as the source material of silver and iodine. The hole concentration was successfully controlled in the range from 2.0×1024 to 9.0×1024 m−3 by doping 100 to 700 mol ppm Ag2Te, and from 3.5×1023 to 4.5×1024 m−3 by doping 100 to 650 mol ppm PbI2. In the case of PbI2 doping, the conduction type was changed at about 700 mol ppm PbI2, and the electron concentration was controlled in the range from 5.0×1022 to 5.0×1025 m−3 by doping 700 to 6000 mol ppm. Scattering factor r was estimated for both p- and n-type PbTe from the temperature dependence of Hall mobility. Thermal conductivity was calculated in terms of carrier concentration by evaluating the lattice (κph) and electronic (κel) thermal conductivities. The κel was estimated on the basis of Fermi integral by using observed data of α and r, where the κph was estimated to be 2.15 Wm−1 K−1 using the calculated κel value and the literature κ data for undoped PbTe. Maximum figure-of-merits (Zmax) of PbTe at 300 K were 1.21×10−3 K−1 for the n-type at n=2.76×1024 m−3 (2000 mol ppm PbI2) and 1.38×10−3 K−1 for p-type at p=2.34×1024 m−3 (200 mol ppm Ag2Te)抄録全体を表示PDF形式でダウンロード (522K) -
江 莞, 内山 哲夫, 南雲 睦, 坂上 智1997 年 61 巻 3 号 p. 247-248
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーPDF形式でダウンロード (262K) -
柴田 俊夫, 山田 智之, 藤本 愼司1997 年 61 巻 3 号 p. 249-250
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーPDF形式でダウンロード (246K)
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