巻号一覧
52 巻, 9 号
選択された号の論文の11件中1～11を表示しています
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高山 善匡, 杜澤 達美, 加藤 一, 古城 紀雄, 堀 茂徳1988 年 52 巻 9 号 p. 835-842
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーThe influence of grain size distribution on the estimation of mean grain size has been investigated. A calculation of the mean grain size by the intercept (Heyn’s) or the planimetric (Jeffries’) method was carried out for a grain structure model. In the model, the grain shape and the grain diameter (equivalent volume diameter) D were reasonably set to be the tetrakai-decahedron and to have a log-normal distribution, respectively.
As the result of the calculation, the following equations are derived for the intercept and the planimetric methods;
(This article is not displayable. Please see full text pdf.)
\ oindentwhere Dg is the geometric mean grain diameter and σg is the geometric standard deviation for D. The calculated value by the intercept method, lcal was in good agreement with the experimental value, \barlex. The mean grain sizes obtained experimentally revealed its clear dependence on σg, which corresponded well to that of the calculated sizes. These suggested that the grain size distribution should have a significant effect on the estimation of the mean grain size.抄録全体を表示PDF形式でダウンロード (995K) -
三村 耕司, 南條 道夫1988 年 52 巻 9 号 p. 843-851
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーRecently H2-Ar plasma arc melting, using a gas mixture of hydrogen and argon as a plasma generating gas, has been recognized to be available for refining of various metals.
In this work, deoxidation and decarburization of crude tantalum, prepared by carbon reduction of Ta2O5 with Ar plasma arc heating, has been investigated by using H2-Ar plasma arc melting. Also the possibilities and conditions for winning high-purity and ductile tantalum metal has been examined.
The oxygen and carbon contents in tantalum obtained by carbon reduction smelting are dependent on the carbon to Ta2O5 mixing mole ratio, and the product of (%O) and (%C) in each tantalum is found to be almost constant. Therefore, The carbon/oxygen ratio in tantalum can be adjusted by changing the C/Ta2O5 ratio for the refining process that follows.
At the subsequent stage of H2-Ar plasma arc melting, oxygen in tantalum can be quickly liberated but carbon is scarcely removed. As a result, ductile tantalum whose sum of oxygen and carbon is less than 100 mass ppm can be produced by the excellent deoxidation effect of H2-Ar plasma arc melting for a high oxygen- and low carbon-bearing tantalum. Deoxidation is considered to be mainly caused by dissociated and activated hydrogen atoms in the H2-Ar plasma gas. The evaporation of tantalum suboxide and tantalum, known in electron beam melting, is very small in this stage so that the loss of tantalum can be reduced.抄録全体を表示PDF形式でダウンロード (1356K) -
尾崎 敏範, 石川 雄一1988 年 52 巻 9 号 p. 852-858
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーMechanical and corrosion properties of 13 mass%Cr martensitic stainless steels containing 2∼5 mass% nickel were studied in various tempered states. Effects of metallurgical variable were examined by the following tests: (a) Conventional mechanical and metallurgical tests, (b) selective corrosion test in 0.88 kmol/m3 HNO3 at 293 K, and (c) slow strain rate stress corrosion cracking test in high purity water at 561 K. The following results are obtained:
(1) The 13%Cr martensitic stainless steels containing 3.5∼5 mass% nickel shows superior mechanical properties and machinability to those with 0∼2 mass% nickel.
(2) However, a higher nickel addition lowers the Ac1 point to the actual tempering temperature range. This makes it difficult to choose the tempering condition which satifies the mechanical properties needed for hydraulic machinery.
(3) The susceptibility to selective corrosion increases with increasing nickel content and selective corrosion occurs in a wide temperature range and consequently the selection of the tempering temperature range is limited.
(4) Active path type stress corrosion cracking behavior is closely related to the selective corrosion behavior.
In conclusion, it is desirable to lower the nickel and carbon contents in the steel and to carefully select the tempering temperature yielding good mechanical properties without giving rise to susceptibility to selective corrosion.抄録全体を表示PDF形式でダウンロード (1726K) -
劉 正堂, 越後谷 淳一, 須藤 一, 塚本 哲治1988 年 52 巻 9 号 p. 859-864
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーUsing the transmission electron microscope, the growth morphology, orientation relationships and interface structure have been investigated for TiC and TiN films deposited on WC-Co alloys by chemical or physical vapor deposition (CVD or PVD). CVD-TiC films on the WC-Co alloys were grown in granular form and their interfaces were irregular. The TiC/WC orientation relationship was given as (0001)WC\varparallel(1\bar11)TiC and [\bar1100]WC\varparallel[\bar112]TiC. PVD-TiN films on WC-Co alloy were grown in columnar form. TiN grains showed particular orientation relationships with WC grains. One of the relationships was the same as that observed for TiC/WC, and the other was [0001]WC\varparallel[1\bar10]TiN, (10\bar10)WC\varparallel(111)TiN. CVD-TiN films on the WC-Co alloys showed the change in growth morphology from the granual form at the initial stage of growth to the columnar form.抄録全体を表示PDF形式でダウンロード (1523K) -
越後谷 淳一, 劉 正堂, 須藤 一, 塚本 哲治1988 年 52 巻 9 号 p. 865-871
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーScratch test has been done for chemically vapor deposited (CVD) TiC and physically vapor deposited (PVD) TiN on WC-Co alloy substrates using the pyramidal indentator. The acoustic emission has been observed accompanied by cracking in the film and detaching of the film from the substrates at the interface. The AE singnals increased abruptly at the critical load at which the detachment began to occur and were constant after critical loading. The critical load corresponds to the detaching of the film from the substrates at the interface. The detached width after scratching also increased with load and was apart from the diagonal of the indentator from the critical load. The scratching depth at the critical load was 1/2-3/5 of the film thickness, which means the indentor did not reach the interface. These results were understood from the introduction of lateral cracks at the unloading by passing through the indentator.抄録全体を表示PDF形式でダウンロード (2302K) -
大西 忠一, 茨木 良昭, 伊藤 太一郎1988 年 52 巻 9 号 p. 872-877
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーIn order to improve fracture toughness and SCC properties and to keep high strength of the T6 level, a three-step aging process (RRA) was investigated for 7475 aluminum alloy. To keep the strength of the T6 level and simultaneously to improve both properties, the usual T6 condition was suitable for the first step aging. For the second step aging (retrogression), the improvement of the properties became more remarkable with increasing temperature and time. However, the strength decreased in the case of over-aging of the retrogression. For the final step aging (re-aging), it was preferable to increase the aging temperature and time to an extent within the permissible range of loss in strength. In conclusion, the present results suggest that the maintenance of high strength and improvements in fracture toughness and SCC properties can be simultaneously effected by the optimum RRA process, and the conventional over-aged treatments, accompanying a loss of strength, such as T76 and T73 may be replaced by the RRA process.抄録全体を表示PDF形式でダウンロード (1253K) -
水内 潔, 大神田 佳平, 大中 逸雄, 稔野 宗次1988 年 52 巻 9 号 p. 878-885
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーIn oder to obtain useful information about the improvement of mechanical properties of Fe-30(mass)%Cr-5%Al alloys containing Ce, some examinations were made on these alloys, as cast and as rolled, using various techniques such as the tensile test, optical microscopy, electron prove microanalysis and X-ray diffraction.
The experimental results are as follows.
[A] The Alloy, without Ce: (1) Mechanical properties are remarkably improved by hot rolling. (2) In advance of cold rolling, it is neccessary to roll at 1273 K. When cold rolled beyond 30%, the tensile strength of the alloy is 750 MPa and the elongation is 20%.
[B] The alloy, with Ce: (1) Increasing Ce addition decreases the amount of Cr23C6 by the precipitation of R2M17 intermetallic compounds. The alloys with less than 0.16%Ce additions can be rolled at 1273 K. (2) With increasing reduction, the grain size appears much smaller. When cold rolled beyond 30%, the tensile strengh of the alloy is 750 MPa and the elongation is 15%.抄録全体を表示PDF形式でダウンロード (1693K) -
川口 健一, 呉 詳秀, 落合 庄治郎, 長村 光造1988 年 52 巻 9 号 p. 886-893
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーIn order to investigate the mechanism of crystal growth and superconducting properties of V3Ga compound as well as the influence of third element additions, the sandwich-type diffusion couples, which consisted of Cu-Ga or Cu-Ga-M (M=Al, Ti) alloy sheets and pure V foil inserted between them, were prepared.
The couples were heat-treated at temperatures between 923 and 1073 K to form the V3Ga compound.
The growth rate of the compound layer was enhanced by the Al addition, where V3Ga grains tended to become columnar when the specimen was annealed for a long time. On the other hand, a fine equiaxed grain structure was formed for the specimen with Ti addition by any annealing treatment.
Considering the time-exponent in the function, d=ktn, where d and t are the layer thickness and the time, respectively, it was suggested that the diffusion of Ga in the V3Ga compound controls the overall rate of crystal growth.
The relation between the maximum global pinning force, Fp,max and the grain size was investigated. It was concluded that Fp,max depends on the reciprocal grain size for the specimen without the third element.
The critical current density at a high magnetic field was found to be improved by the Al addition owing to the so-called peak-effect.抄録全体を表示PDF形式でダウンロード (1546K) -
金子 寿輝, 北 芳明, 津村 誠, 安藤 寿1988 年 52 巻 9 号 p. 894-898
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーHigh-resistivity (Cr, Ti)Si2 thin films favorable for the resistors of thermal printing heads have been prepared by DC magnetron sputtering. The electrical resistivities of (Cr1−xTix)Si2 films show a maximum value of 60 μΩm at x=0.37, which is three times larger than that of the CrSi2 film. By heating the as-deposited (Cr0.63Ti0.37)Si2 film up to 723 K, the resistivity increases by 15%. After it is once heated up to 723 K, there is no change in resistivity by the same heat treatment. Using the (Cr0.63Ti0.37)Si2 film, the resistors of thermal heads with an Al electrode and a SiO2 protective layer were constructed for the wax transfer printing. The resistors have a sufficient lifetime for the pulsed-current load test.
Devising the shape of the resistors, the half-tone printing covering a wide range of optical densities divided into 32 steps has been achieved.抄録全体を表示PDF形式でダウンロード (671K) -
野沢 康人, 岩崎 克典, 五十嵐 芳夫, 谷川 茂穂, 徳永 雅亮1988 年 52 巻 9 号 p. 899-905
発行日: 1988年
公開日: 2008/04/04
ジャーナル フリーAnisotropic Nd-(Fe, Co)-B-M(M=Ga, Hf, Zr, Al, Zn, Nb, Ta, Dy and Fe) magnets were prepared by melt-spinning and hot deformation (die-upsetting). Intrinsic coercivity and irreversible loss are dramatically improved when Ga is added. Ga is condensed in a boundary phase (1 nm in thickness) and a Nd-rich phase. Ga seems to strengthen the pinning force of domain walls at grain boundaries. Addition of Ga and substitution of Co improved the coefficient of remanence and the irreversible loss.
Permanent magnet properties obtained for Nd14FebalCo15B6Ga0.75 are as follows: Br=1.20 T, iHc=1.66 MA/m, bHc=0.92 MA/m, (BH)max=274 kJ/m3. Temperature coefficient of Br is −0.067%/K (average value between 298 and 423 K) and an irreversible loss after exposure up to 453 K is 3.2% (B⁄H=−2).抄録全体を表示PDF形式でダウンロード (1261K) -
坂田 君子1988 年 52 巻 9 号 p. 906-907
発行日: 1988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 (810K)
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