巻号一覧
57 巻, 3 号
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岩本 信也, 横尾 一, 井上 裕文1993 年 57 巻 3 号 p. 241-244
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーA partially stabilized zirconia (PSZ) was implanted with N+ ions and the wettability against the Zr-47 mass%Cu alloy was measured by the sessile drop method. Surface characterization of the implanted 3Y-PSZ was performed using XRD and XPS.
The contact angle of PSZ against the Zr-47Cu alloy at 1273 K was improved from about 60 to 45 degrees by the implantation. The results of XRD showed that tetragonal phase of zirconia was converted to a monoclinic phase by the implantation. XPS indicated that the surface of the implanted PSZ was more metallic as compared with the inside of the material. This implies that zirconia was reduced by N+ ion implantation. The improvement of wettability is considered to be attributable to the formation of the metallic and active layer up on the surface.抄録全体を表示PDF形式でダウンロード (418K) -
角田 直人, 岡野 哲之, 岡田 達明1993 年 57 巻 3 号 p. 245-253
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーPrecipitates in Al-Au dilute alloys are η-phase (Al2Au), which appear in the form of plate on the matrix cube planes. However, it is likely that Au-rich zones (GP-zone) are formed at the beginning stage of precipitation. Consideration of the atomic radii of Au and Al leads us to expect the spherical shape. In this paper, electron microscope observation of the precipitates in an Al-0.2 mass%Au alloy aged under various conditions was made to study the precipitation process in detail.
Small platelets about 1-4 nm in size appear on the {100} planes at the beginning stage of the precipitation. The platelets thicken and lengthen with aging and finally form the η-phase. It follows from the diffraction patterns and the high resolution images of the various forms of precipitates that the small platelets are not the η-phase.
High resolution images of the η-phase precipitates show that the interface between the precipitates and the matrix is not steep in atomic scale and a transition phase exists around the interface. The transition phase can be considered as an intermediate state of the transformation from the Al to the η-phase.
It is concluded that the precipitation process of Au in Al is as follows. The Au atoms aggregate to form the small platelets at the beginning stage of precipitation and the platelets grow up to be the η-phase forming the transition phase around them.抄録全体を表示PDF形式でダウンロード (5787K) -
木村 勇次, 鎌田 政智, 高木 節雄1993 年 57 巻 3 号 p. 254-260
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーThe phase decomposition behavior of (δ+γ) two phase stainless steel powder at elevated temperatures has been investigated in association with the amount of strain given through mechanical milling treatment. The powder with a composition of Fe-24 mass%Cr-8 mass%Ni was prepared by N2 gas atomization. The structure of the as-received powder is fully ferritic at room temperature but transforms to (δ+γ) two phases at elevated temperatures.
The strain stored within the δ phase powder through milling treatment increases with inceasing milling time and has a large effect on refining the (δ+γ) two-phase structure obtained after annealing. For example, the 360 ks milled powder has a fine (δ+γ) two-phase structure of less than 2 μm in the mean grain size after 1173 K-3.6 ks annealing. During heating to a given annealing temperature, the δ phase powder milled sufficiently transforms allotropically to the almost full γ structure because of the increased driving force for the γ phase nucleation, and then the δ phase again precipitates from the γ phase during isothermal annealing reaching the equilibrium structure and composition of the (δ+γ) two-phase.
Those grains, however, easily coarsen during annealing at temperatures higher than 1273 K. Addition of alumina fine powder(0.06 μm) is quite effective in refining the (δ+γ) two-phase structure, because alumina particles not only suppress the grain growth at such a high temperature but also promote γ grain nucleation through the retardation of recovery in the deformed δ phase.抄録全体を表示PDF形式でダウンロード (923K) -
竹元 嘉利, 飛田 守孝, 榊原 精1993 年 57 巻 3 号 p. 261-267
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーThe mechanism of the ω→α phase transformation following isothermal aging has been studied on a single crystal of a Ti-14 mass%Mo alloy. For isothermal aging at 623 K, the specimen showed a maximum hardness at 1×106 s and subsequent softening. At 3×105 s to 1×106 s the ω particle abruptly grew so far as about 100 nm by combining each other. During further aging, however, the change in ω size was not observed. A part of the large scale ω was transformed to the α phase after aging 1×106 s. The orientation relation between the ω and α phases was revealed to be (11\bar20)ω\varparallel(0001)α and [0001]ω\varparallel[11\bar20]α by the image of HR-TEM and model simulation. The α phases formed according to the orientation relation obeyed the well-known Burgers relation. However, the growth direction of precipitate was not [0001]α.
For isothermal aging at 823 K for 1×105 s, needle-like precipitates of Type 1α and Type 2α were observed. It was elucidated using micro-beam diffraction technique for the individual precipitates that both types of α phases obeyed the Burgers relation, and that the difference between Type 1α and Type 2α was merely in the morphology of growth direction of the precipitates. It was suggested that Type 1α was directly formed from the β matrix through the transformation mechanism dominated by thermal diffusion, while Type 2α was formed via ω from β.抄録全体を表示PDF形式でダウンロード (1557K) -
宗木 政一, 河部 義邦, 高橋 順次1993 年 57 巻 3 号 p. 268-273
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーEffects of the solution treatment and the aging treatment on the strength, ductility and toughness of a Ti-3Al-8V-6Cr-4Mo-4Zr alloy have been investigated. In the solution treated and aged condition, the 0.2% yield and tensile strengths exhibited approximately constant values irrespective of the beta grain size. Both elongation and reduction in area decreased with increasing beta grain size. The notched tensile strength and the plane strain fracture toughness were independent of the beta grain size but strongly dependent on the strength level. Both the strength-ductility and the strength-toughness balances of a Ti-3Al-8V-6Cr-4Mo-4Zr alloy were satisfactory with no embrittlement in all the aging conditions examined.
In comparison with Ti-10V-2Fe-3Al and Ti-15V-3Cr-3Sn-3Al alloys, there are great differences in strength-ductility and strength-toughness balances when aged below 673 K. But no difference on their balances could be observed in the material aged above 723 K, although their strength levels are different. In order to strengthen the beta titanium alloys more than 1300 MPa, it is necessary to refine the grains less than 45 μm by applying any treatment.抄録全体を表示PDF形式でダウンロード (744K) -
前 健彦, 日比野 委茂, 砂田 聡, 佐貫 須美子, 新井 甲一1993 年 57 巻 3 号 p. 274-281
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーThe effect of Ga content on the corrosion resistance of Al-0.9 mass%Mg2Si alloys in a dilute HClO4 solution was investigated by means of electrochemical measurements such as polarization curves, immersed corrosion tests, scanning electron microscopic observations of corrosion surface and transmission electron diffraction analysis of equilibrium precipitates.
The main results obtained are summarized as follows:
(1) The precipitate of Al-0.9 mass%Mg2Si alloys are equilibrium Mg2Si independent of Ga content. The distribution of Mg2Si precipitates is almost uniform, and the mean values of surface area ratios of precipitates are about 4.6%.
(2) The corrosion resistance of Al-0.9 mass%Mg2Si alloys decreases with increasing Ga content: Al-0.9 mass%Mg2Si>Al-0.9 mass%Mg2Si-0.2 mass%Ga>Al-0.9 mass%Mg2Si-0.4 mass%Ga. The corrosion of the alloys is uniform under equilibrium conditions. However, the fall of precipitates was observed partly on corroded surfaces.
(3) The galvanic corrosion occurred between the Mg2Si precipitate and a matrix phase. The Mg2Si precipitate acts as an anode. On the contrary, the matrix phase act as a cathode regardless of Ga content. The selective anodic dissolution of Mg from the Mg2Si precipitates is observed on corroded surfaces.抄録全体を表示PDF形式でダウンロード (1391K) -
横山 誠二, 小久保 貞男, 斎藤 己由, 伊藤 公允, 川上 正博1993 年 57 巻 3 号 p. 282-288
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーMolten aluminum was evaporated in a cold gas stream of Ar+O2 mixture in order to investigate both the evaporation rate of the liquid metal and the characteristics of condensed particle in the reactive gas stream. Experiments were carried out under various oxygen partial pressures (PO2), temperatures and total gas flow rates using a levitation melting apparatus. The relations between the evaporation rate and PO2 could be classified into three regions; i.e. low, medium and high PO2 regions. The rate in each PO2 region was discussed using a counter flux model of aluminum vapor and oxygen in the boundary layer around the levitated specimen.
The results obtained in each PO2 region were summarized as follows:
(1) Low PO2 region: As most oxygen reacted with aluminum particles after condensation of the aluminum vapor, the evaporation rate was almost the same as the one in the Ar gas stream irrespective of PO2. The condensed particles were a mixture of aluminum and widely defined γ-Al2O3. The amount of the γ-Al2O3 increased with an increase of PO2.
(2) Medium PO2 region: As oxygen diffused beyond the site where the aluminum vapor nucleated, it reacted with the aluminum vapor. The boundary layer thickness for the aluminum vapor decreased with an increase of PO2, so that the evaporation rate increased linearly. The condensed particles were almost widely defined γ-Al2O3. As a whole, it could be said that the mean particle diameter decreased with increasing PO2 and total gas flow rate and with decreasing temperature.
(3) High PO2 region: As oxygen diffused onto the levitated specimen surface, an oxide film covered on the specimen surface. Accordingly, the vaporization of aluminum ceased and no particle was obtained.抄録全体を表示PDF形式でダウンロード (962K) -
林 台煥, 木原 宏, 林 宏爾1993 年 57 巻 3 号 p. 289-295
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーThe effect of the added carbon content (0-2.0 mass%) on the densification of two kinds of carbonyl iron micropowder (Reduced Grade; 5.3 μm, 0.46 mass%O, 0.03 mass%C, 0.0044 mass%N, and Straight Grade; 4.2 μm, 0.79 mass%O, 0.76 mass%C, 0.65 mass%N), which were sintered at 1573 K for 3.6 ks in vacuum and H2 gas, was investigated.
The results obtained were as follows: (1) Reduced Grade powder: Vacuum sintered compacts of Fe+(0-0.2)mass%C and H2 gas sintered compacts of Fe+(0-1.0)mass%C compacts showed incomplete densification. However, the vacuum sintered compacts with the addition of more than about 0.4 mass% carbon and the H2 gas sintered compacts with the addition of more than about 1.2 mass% carbon showed complete densification. (2) Straight Grade powder: In the case of vacuum sintering, the densification was incomplete at the addition of 0-0.4 mass% carbon, although the total amount of carbon was 0.76-1.1 mass%. However, it became complete above about 0.5 mass% (the total amount of carbon was about 1.26 mass%). In the case of H2-gas sintering, the densification was incomplete up to 2.0 mass% carbon (the total amount, 2.76 mass%). (3) The oxygen content of the completely densified compacts were as low as about 0.006-0.002 mass%, in contrast to the value of more than 0.01 mass% for the incompletely densified compacts. (4) These results could be explained from the viewpoint of our theory that “the complete or incomplete densification depends on whether the equilibrium pressure of the CO gas which is generated by the reduction reaction and trapped in the closed pores is lower or higher than the surface stress of closed pores”, when it is assumed that the added carbon is able to reduce more easily the oxide on the surface of each iron particle, compared with the carbon which is originally contained inside of the particles, and then promotes the diffusing-out of carbon or oxygen from the inside of iron particles to the atmosphere before the isolation of pores.抄録全体を表示PDF形式でダウンロード (2411K) -
薩田 寿隆, 長谷川 正, 原田 展道, 浅井 滋生1993 年 57 巻 3 号 p. 296-300
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーUsing the method of discharge in liquid nitrogen, eleven kinds of metals (Al, Ti, V, Fe, Ni, Cu, Zr, Nb, Mo, Ta and W) were pulverized and the powder characteristics and discharge behaviour were investigated. Based on the phases of the produced particles, the metals are classified into two groups. One is the group of/Zr, Ti, Al, Ta, Nb, and V/for which the phase of the particle was that of a nitride compound, and the other is the group of/Mo, W, Fe, Ni and Cu/for which the phase of the particle was the same as that of the pulverized electrode. In the former group the free energy for formation of a nitride compound takes a negative value nearly up to the melting point of each metal, and in the latter group it does a positive value at the melting point of each metal. Furthermore, the shape of the produced particles was irregular in the former group and almost spherical in the latter one. The discharge behaviour of each metal is classified into three groups, each of which can be explained by the ability for nitrization, work function and thermal properties.抄録全体を表示PDF形式でダウンロード (756K) -
朴 榮哲, 李 揆暢, 三原 毅, 伊達 和博1993 年 57 巻 3 号 p. 301-306
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーThe purpose of this study was to develop a non-destructive material evaluation method of aluminum alloy base metal matrix composite (MMC) by ultrasonics. Five aluminum base MMC specimens in which the fractional ratios of fiber were changed from 0% to 31% were fabricated. The relationship between the acoustic properties, microstructural features and elastic constant were compared. The ultrasonic velocity method was, then, useful for nondestructive elastic constant measurement of composite materials, since this method had the same measurement accuracy as the conventional strain measurement method. Furthermore, the velocity and attenuation parameter are also related to the fractional ratio of fiber and these relations may be utilized for the ultrasonic non-destructive evaluation of fiber structure in MMC.抄録全体を表示PDF形式でダウンロード (1288K) -
小野 修二, 斎藤 正洋, 松尾 信太郎1993 年 57 巻 3 号 p. 307-311
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーRecently, a new high strengh 18%Cr cast stainless steel (C≤0.04%, Cr: 16∼18%, Ni: 5∼7%, Mo: 1%) has been put into practical use for marine propellers. The erosion resistance of this steel was compared with that of other cast stainless steels such as martensitic cast stainless steel and nickel aluminum bronze. The results are summarized as follows:
(1) Pitting potential of the steel, which consists of martensitic, austenitic and ferritic phases, is 0.27∼0.33 V(vs Ag/AgCl/KCl) in sea water. This result shows the corrosion resistance of the steel is better than that of SUS304 and martensitic cast stainless steels.
(2) The hardness of the steel was lower than that of martensitic cast stainless steel. The erosion resistance of the steel was, however, higher than that of other cast stainless steels. This was due to hardening of the surface of the erosion test specimen caused by the stress induced martensitic transformation of the residual austenitic phase.
(3) The erosion resistance of the steel was about two times higher than that of nickel aluminum bronze.抄録全体を表示PDF形式でダウンロード (384K) -
麻生 節夫, 菅原 勉, 田上 道弘, 後藤 正治1993 年 57 巻 3 号 p. 312-319
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーThe relation between eroding rate (Wk) and slurry speed (V) was given by Wk=KVn (K: constant) on sand-erosion of 15%Cr and 15%Cr-3%Ni eutectic white cast irons. The experimental expression of the eroding rate, which was obtained through the slurry temperature and slurry speed dependences of the sand-erosion characteristics, was in good agreement with the measured eroding rates. The erosion behavior and the eroded sureface structure suggested the change of the eroding mechanism at low and high-slurry speed ranges. The change of the eroding behavior was assumed to be related to the yield stress of the specimens. However, the applied stress due to particle collision at the change of the eroding behavior was calculated to be much higher than the yield stress. This difference was speculated to be due to the composite microstructure of eutectic carbide and the matrix in the high chromium white cast irons.抄録全体を表示PDF形式でダウンロード (1410K) -
渡邊 清, 篠原 猛, 佐藤 正樹1993 年 57 巻 3 号 p. 320-324
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーThe Fe73.74Si16.56Al9.70 (Sendust) and Fe73Al27 (Alperm) alloys with soft magnetic properties were investigated by using a spin-echo method of nuclear magnetic resonance, a magnetic balance and an X-ray diffractometer. The D03-type and B2-type alloys have been made by heat-treatments and the forced process strain.
The NMR spectrum is divided into two different frequency regions of which boundary is around 50 MHz. At the low frequency side, the spectrum with Sendust D03-type shows an intense peak at 18 MHz for 27Al nuclei, the peaks at 28 and 46 MHz for 57Fe nuclei, and a peak at 31 MHz for 21Si nuclei. The spectrum of B2-type shows three peaks at 25, 32 and 40 MHz for 27Al nuclei.
The spectrum of the Alperm D03-type shows an intense peak centered at 29 MHz and two weak peaks for the 27Al nuclei, and a weak peak at 46 MHz for 57Fe nuclei. The spectrum of the B2-type shows a broad peak centering at 36 MHz and two weak peaks for 27Al nuclei. These alloys exhibit peculiar spectra for the different crystal structure types.
At the high frequency side, the spectra of all alloys show a similar broadening distribution. It is considered that aluminum atoms are distributed at several sites depending on the deviation from the stoichiometric composition and disorder arrangements, because the hyperfine field of aluminum is influenced by iron.抄録全体を表示PDF形式でダウンロード (424K) -
松島 忠久, 斎藤 一男1993 年 57 巻 3 号 p. 325-331
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーIntermetallic compound TiAl specimens of near-stoichiometric compositions, 34, 36 and 38 mass%Al, were implanted with 150 keV nitrogen ions to doses ranging from 2×1021 to 17×1021 ions/m2 at room temperature. The surface hardness of these implanted specimens reached a maximum at doses of 5∼8×1021 ions/m2, but thereafter it decreased. For the Ti-rich specimen the hardness reached over two times that of the unimplanted state at a dose of 5×1021 ions/m2. X-ray diffraction and transmission electron microscopy studies showed that AlN and Ti2N were produced in the form of fine particles of about 10 nm diameter. TiN nitrides were not observed even after a high dose of 17×1021 ions/m2 and subsequent annealing at 773∼973 K. For higher doses the depth profiles of nitrogen atoms became flattened and broadened with a maximum nitrogen concentration of approximately 48 at%. The stress-corrosion induced microcracks that appear on the mechanically polished surfaces of TiAl specimens, are prevented by nitrogen ion implantation. The corrosion resistance is also remarkably improved by high-dose nitrogen implantation.抄録全体を表示PDF形式でダウンロード (1657K) -
岡崎 義光, 伊藤 喜昌, 伊藤 敦夫, 立石 哲也1993 年 57 巻 3 号 p. 332-337
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーTitanium alloys for medical implants were casted using 5∼20 mass%Zr, 10∼20%Sn, 4∼8%Nb, 2∼4%Ta and 0∼0.2%Pd as alloying elements instead of using harmful Al and V.
The alloys were forged in their α and α+β regions followed by annealing at 973 K for 7.2 ks. The annealed microstructures of the alloys consisted mainly of the acicular structure containing elongated β grains in the range from 10 to 30 vol%.
The room temperature tensile strength of the alloys markedly increased with increasing Sn content, as compared with increasing than Zr content. As a result, the Ti-15%Sn-4%Nb-2%Ta-0.2%Pd alloy surpassed the Ti-6%Al-4%V extra low interstitial alloy for medical implants (ASTM F136-84 standard) in tensile strength as well as in elongation and reduction of area. The tensile strength was further improved by the additions of nitrogen and oxygen.抄録全体を表示PDF形式でダウンロード (710K) -
岡崎 義光, 伊藤 敦夫, 立石 哲也, 伊藤 喜昌1993 年 57 巻 3 号 p. 338-346
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーThe effect of Zr, Sn, Nb, Ta, Pd, N and O on the corrosion resistance of titanium alloys for medical implants was investigated by measuring the anodic polarization curves at 310 K in 5 mass%H2SO4 and 5%HCl solutions deaerated by high-purity N2 gas bubbling. The critical current density for passivation (Ic) and passive current density at 0.6 V vs. SCE of the titanium alloys markedly decreased with increasing Zr, Nb, Ta, and Pd contents in the range from 5 to 20, 4 to 8, 2 to 4 and 0 to 0.2%, respectively, although Sn had an adverse effect in the range from 10 to 20 mass%. The effect of N and O on Ic was undetected. The Ic values decreased linearly with increasing bond order (\barBo) value representing the covalent bond strength between Ti and the alloying elements. The passive films formed on Ti-15%Zr-4%Nb-2%Ta-0.2%Pd alloy in the 5%H2SO4 solution consisted mainly of TiO2, ZrO2, Nb2O5 and Ta2O5, as demonstrated by electron spectroscopy for chemical analysis (ESCA). The anodic polarization properties of Ti-15%Zr-4%Nb-2%Ta-0.2%Pd and Ti-15%Sn-4%Nb-2%Ta-0.2%Pd alloys were found to be superior to those of the Ti-6%Al-4%V extra low interstitial alloy and SUS316L stainless steel.抄録全体を表示PDF形式でダウンロード (656K) -
岡崎 義光, 伊藤 敦夫, 立石 哲也, 伊藤 喜昌1993 年 57 巻 3 号 p. 347-355
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーThe effect of alloying elements on the corrosion resistance of titanium alloys for medical implants was investigated by immersion tests in an aerated 5%HCl solution for 864 ks at 310 K and anodic polarization measurements in a phosphate buffer solution containing chloride (PBS(−)). The concentration of released Ti in the 5%HCl solution decreased with increasing Zr, Ta, and Pd contents in the range from 10 to 15, 2 to 4 and 0 to 0.2%, respectively, although Nb and Sn had an adverse effect in the range from 4 to 8 and 10 to 15 mass%, respectively. However, Zr and Sn alloying over 15% in Ti-(15∼20%)Zr-4%Nb-2%Ta-0.2%Pd and Ti-(15∼20%)Sn-4%Nb-2%Ta-0.2%Pd, respectively, showed very little difference in the concentration of released Ti, compared with those less than 15%. Especially combined alloying of 0.2%Pd and (2∼4%)Ta remarkably decreased the concentration of released Ti in the 5%HCl solution. N addition into the Pd-free Ti-10%Zr-4%Nb-2%Ta-0.1%O alloy increased the concentration of released Ti. The critical currrent density for passivation (Ic) of the titanium alloys in the PBS(−) decreased with increasing Zr, Nb, Ta and Pd contents. The Ic values in the PBS(−) decreased as those in the 5%HCl solution decreased. The concentration of released Ti from the Ti-15%Zr-4%Nb-(2∼4%)Ta-0.2%Pd and Ti-15%Sn-4%Nb-(2∼4%)Ta-0.2%Pd alloys in the 5%HCl solution were less than that from the Ti-6%Al-4%V ELI alloy by a factor of 52∼520.抄録全体を表示PDF形式でダウンロード (2651K) -
譚 毅, 篠田 哲守, 三島 良直, 鈴木 朝夫1993 年 57 巻 3 号 p. 356-361
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリーWith boron-doped NiAl alloys, the solubility of boron, the composition and structure of the precipitated boride and the change in fracture mode due to boron addition have been studied. The solubility of boron is very small on the Ni-rich side of the alloys with a slight increase in its magnitude with deviation from the stoichiometric composition of the alloys, while the solubility of boron on the Al-rich side can be neglected. The structure of the precipitated boride on the Ni-rich side of the NiAl(45 at%Al) alloy is a Cr23C6 type compound, where composition is Ni60Al10B30 and the lattice parameter of which is 1.0542 nm.
The fracture mode for the alloys changes from the intergranular to the transgranular type of fracture as an increase in boron concentration for both sides of Ni- and Al-rich compositions. However, the critical concentration of boron to the mode change in fracture mode is 0.003 mass% on the Ni-rich side, whereas it is 0.02 mass% on the Al-rich side.抄録全体を表示PDF形式でダウンロード (573K) -
1993 年 57 巻 3 号 p. 362a
発行日: 1993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 (22K) -
1993 年 57 巻 3 号 p. 362b
発行日: 1993年
公開日: 2008/04/04
ジャーナル フリー
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