日本金属学会誌
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
63 巻, 10 号
選択された号の論文の20件中1~20を表示しています
  • 蔭山 健介, 加藤 寛, 畑本 隆, 浅沼 孝治
    1999 年 63 巻 10 号 p. 1231-1237
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    Microfracture in piezoceramics influences on its piezoelectric properties and their relationship can lead to development of self-diagnosing material using the piezoelectric properties. In this study, Vickers indentations were carried out to introduce small cracks in PZT specimens the specimens were subjected to a hitting test for evaluation of the piezoelectric properties. Then PZT specimens were bent to extend cracks on the surface of the specimen and the piezoelectric properties were measured. The waveform of a piezoelectric signal had a first positive peak and a second negative peak. An amplitude ratio (rp) of the first peak to the second peak was used to evaluate the piezoelectric properties of specimens. The ratio rp increased with the number of the Vickers indentation on the surface of specimens. When an interval of indentation positions is 0.3 mm, cracks coalesced. When the indentation array is perpendicular to hitting and poling directions, rp increased with the number of Vickers indentation. Following repeated bending of the specimen, the crack propagated successively to increase the ratio rp. Under the same loading conditions rp-crack propagation curves showed the same change and the same increasing ratio of rp occurred just before breaking of specimens. These results show the possibility of prediction of fracture in PZT by measurement of the piezoelectric properties.
  • 原 基, 稗田 大輔, 日向 幸昌
    1999 年 63 巻 10 号 p. 1238-1247
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    The hot corrosion behavior of TiAl intermetallic compound due to molten NaCl has been examined by measuring the mass change of the specimen, observation and analyses of scales formed and electrochemical measurement. The corrosion mass loss of TiAl under a coating of molten NaCl was far larger than those under whole immersion in molten NaCl and under coating of molten Na2SO4. Such a hot corrosion of the TiAl under coating of molten NaCl was due to accelerated oxidation during the initial period. Mass gain of the TiAl due to this accelerated oxidation increased with increasing mass of coating NaCl, O2 concentration in the atmosphere and test temperature. Scales formed after the accelerated oxidation consisted of three layers; an outer layer consisting of rutile-TiO2, a middle layer consisting of α-Al2O3 and an inner layer consisting of a mixture of rutile-TiO2 and Ti2O. In these oxide layers NaCl was detected, showing that molten NaCl penetrated into the scale. The period, during which NaCl was contained in the scale, agreed with that when the accelerated oxidation occurred. This suggests that the molten NaCl contained in the scale contributed to the accelerated oxidation. In molten NaCl, the anodic dissolution reaction and the cathodic reduction reaction of dissolved O2 were active. On the basis of these experimental results, a mechanism for accelerated oxidation in TiAl is presented, in which the growth of the scale proceeds through electrochemical steps at metal/oxide and oxide/molten salt interfaces and a diffusion step for metal and oxide ions in molten NaCl penetrates in the scale.
  • 樋尾 勝也, 細井 祐三, 筒井 光範, 岡部 道生
    1999 年 63 巻 10 号 p. 1248-1254
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    Effects of alloying of Al and Si on anodic polarization of Fe-10Cr alloys have been studied in order to assess the possibility of obtaining a lower Cr content stainless steel. Experimental mesurements have been made on anodic polarization curves in 0.05-1.0 kmol·m−3 H2SO4 aqueous solution, pitting potentials in 3.5%NaCl aqueous solution and repassivation potentials in 0.05 kmol·m−3 H2SO4+0.05 kmol·m−3 NaCl aqueous solution.
    The critical current density for passivation decreased with the increase of Al and Si contents in Fe-10Cr alloys. It was evident that Si exerted a greater influence than Al. The passive current density decreased with increasing Si content. In the case of adding 1%Al, the passive current density decreased, and there was almost no change in the current density in the case of >1%Al addition to Fe-10Cr alloys. The critical current density for passivation and the passive current density increased with increasing concentration of H2SO4. An Fe-10Cr-3Al-3Si alloy showed the lowest critical current density, and an Fe-10Cr-3Si alloy showed the lowest passive current density. It was indicated that the pitting potential moved to noble direction with increasing Si content. On the other hand, it moved to noble direction with Al content until 3%, however this beneficial effect was decreased by more than 3%. In repassivation behavior, an Fe-10Cr-3Al-3Si alloy showed the most noble potential among the alloys investigated. It is suggested that Fe-10Cr alloys containing Al and Si have a corrosion resistance which is equal to or greater than that of Fe-12Cr stainless steel.
  • 張 国鋒, 森下 政夫, 稲田 真樹, 香山 滉一郎
    1999 年 63 巻 10 号 p. 1255-1261
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    Corrosion of NiMo2B2-dispersed Ni-based alloys containing Co, Mn, Cr, Fe, or Cu was examined by measuring the mass loss and the corrosion potential in 6 mass%HNO3 aqueous solution and by metallography. The corrosion was accelerated by addition of Co or Mn while it was retarded by addition of Cr, Fe or Cu. In particular, the addition of Cu greatly improved the corrosion resistance. The corrosion proceeded by a mechanism in which the Ni binding phase worked as anode while the NiMo2B2 phase worked as cathode. The addition of Cu shifted the corrosion potential of the Ni-binding phase to the noble side by about 15 mV, and consequently the difference in the corrosion potential between the Ni-binding phase and that of the NiMo2B2 phase decreased. As a result the preferential corrosion of the Ni-binding phase was extremely retarded.
  • 渋谷 陽二, 塩崎 幹夫, 釘宮 哲也, 冨田 佳宏
    1999 年 63 巻 10 号 p. 1262-1268
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    Carbon nanotubes are expected to be one of future fiber materials with extremely high tensile rigidity. Many reports concerning their physical and chemical properties have been published, while there are not enough studies on mechanical properties yet. In the present paper, the structural stability and the mechanical deformation behavior of nanotubes are investigated using the molecular dynamics.
    From relaxation process of a nanotube made of one graphite sheet (graphine) at room temperature, a tube with a relatively large radius is thermodynamically unstable due to forming the local planar substructure. This is the reason why it is the global minimum energy configuration of the original graphine. The multi-walled nanotube with weak van-der-Waals type interaction between layers is, thus, necessary to keep its shape round for the large-sized tubes.
    Nano-scaled tensile tests of both the normal and the helical tubes show that they have an extremely high elastic modulus of about 0.5 TPa whose order has been observed in the previous experimental works.
    As bending tests, a vertical following force is applied to the free end of a single-walled nanotube cantilever. The tube responds linearly (linear elastic relation) and then buckles at a certain critical load whose behavior is similar to the well-known macroscopic thin pipe over length scales. Two transition mechanisms related to topological changes of the basic carbon hexagons are observed; one is the creation of two pairs of pentagons and heptagons, and the other is the motion of a pair of them. Since the transformed configuration has been found to be the local minimum energy configuration, it remains after unloading. The helical tubes provide almost the same buckling behaviors notwithstanding lack of the geometric symmetry.
  • 江村 聡, 萩原 益夫
    1999 年 63 巻 10 号 p. 1269-1276
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    The orthorhombic (O) phase based on the compound Ti2AlNb(Ti-25Al-25Nb(mol%)) has a higher strength-to-density ratio and better room temperature ductility than conventional titanium aluminides such as TiAl and Ti3Al. In the present study, orthorhombic Ti-22Al-27Nb alloy was produced by the blended elemental (BE) powder metallurgy (P/M) method, and the microstructures and mechanical properties such as tensile and high cycle fatigue were evaluated.
    Homogeneous BE P/M Ti-22Al-27Nb was successfully produced by using extra low chlorine Ti powder and Al-Nb master alloy powder with a particle size smaller than 45 μm. The microstructure in the as-HIP’ed condition consisted of O, α2 and β phases. The O and β phases were distributed in the interior of the grains whereas the α2 phase was mainly formed along the grain boundaries. The post-HIP heat treatment at 1173 K for 36 ks made the distribution of these three phases more homogeneous. Although the tensile specimen was broken before the peak tensile strength was attained in the temperature range up to 923 K, both 0.2% proof stress and fracture strength were higher than those for the Ti-6Al-2Sn-4Zr-2Mo alloy. The Young’s modulus and high cycle fatigue strength at 107 cycles in the as-HIP’ed condition were 129 GPa and 480 MPa, respectively. High cycle fatigue strength was increased to 540 MPa by the post-HIP heat treatment.
  • 野瀬 正照, 長柄 毅一, 横田 勝, 周 民, 佐治 重興, 中田 幹子
    1999 年 63 巻 10 号 p. 1277-1282
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    We have already reported that the conditions for obtaining gold-yellow TiN films by reactive sputtering method without bias application. It is well known that the qualitative relationship between the color and the electrical resisitivity of TiN films such as “the golden yellow TiN films have low resistivity”. However the reason for this relationship is not clear. The purposes of the present work are to investigate the quantitative relationship between the colorimetric properties and electrical resistivity of these films and to examine the cause for these properteis. For these purposes, the color of the films was evaluated by means of the chromaticity coordinates, x and y, and the stimulus value or luminous reflectance, Y, which is an index of the brightness based on a CIE standard colorimetric system. TiN films having several kinds of properties were obtained, and a study of their electrical and colorimetric properties has provided the following conclusions: (i) The colorimetry of the films is affected by both the mixing ratio of Ar/N2 gas and the total gas pressure. Particularly, the luminous reflectance, Y, varied greatly with a change in total gas pressure of Ar and N2 gas. (ii) Even without bias application, a gold-colored TiN film with higher reflectance, Y, has been obtained by deposition at an appropriate mixing ratio of N2/Ar and also under lower total gas pressure, namely, ρ=0.31 μΩm and Y=49% for the films deposited at 0.15 Pa. (iii) As the total gas pressure was increased, the column size, the surface roughness and oxygen content clearly showed an increase. Thus, the films deposited under an atmosphere higher than 0.15 Pa had higher resistivity and lower reflectance. (iv) Based on our results, the quantitative relationship between the resistivity, ρ, and the luminous reflectance, Y, of the TiN films is shown by the representation of ρ=775Y−2.
  • 尾中 晋, 安藤 嘉門
    1999 年 63 巻 10 号 p. 1283-1289
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    The average Young moduli are calculated analytically for composites containing aligned spheroidal second-phase particles whose axis of rotation is parallel to an external uniaxial stress. The Mori-Tanaka concept of “average stress” together with the equivalent inclusion idea of Eshelby is used for the calculations to include interactions between second-phase particles. The variation of the average Young moduli with the transitions of second-phase shapes from plate-like to fiber-like through spherical shapes are shown for isotropic elastic moduli of a matrix and second phase. When the volume fraction of the second phase and the Young moduli of the matrix and second phase are fixed, the Poisson ratios significantly change the variation of the average Young moduli of the composites with the transitions of the second-phase shape. Maps to show the Poisson-ratio effect are derived. Results obtained are compared with results given by the Reuss and Voight approximations where equi-stress and equi-strain conditions in the matrix and second phase are assumed respectively. For certain combinations of the Young moduli and the Poisson ratios of the matrix and second phase, the average Young moduli of the composites with various second-phase shapes are always larger than the value given by the Voight approximation, the rule of mixture of the Young moduli. We have shown that it is possible that the average Young moduli of the composites can be larger than those of the matrix and second phase.
  • 三浦 成人, 渡辺 和雄, 淡路 智, 本河 光博, 石川 清一
    1999 年 63 巻 10 号 p. 1290-1294
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    A poly Bitter coil is desired as the resistive coil of a hybrid magnet from the viewpoint of easy fabrication. Recently, high silver content and high-strength CuAg alloy is developed. This alloy, however, is so hard. It is difficult to make thin and very flat plates of the CuAg alloy with large area. We succeeded in fabricating 26 mass%Ag-Cu plates with the thickness of 0.8 mm and an area of 340 mm×340 mm square by using a special rolling process and heat treatment. The plates have a maximum 0.2% proof stress greater than 670 MPa and a mean electrical conductivity greater than 78%IACS at room temperature. The magnetoresistance of CuAg alloys were measured up to 15 T magnetic fields. The increase in the resisitivity was very small.
  • 小椋 謙, 近藤 雅之, 森本 立男, 武田 恭之, 納富 啓
    1999 年 63 巻 10 号 p. 1295-1303
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    The thermal expansion of plasma sprayed Y2SiO5 coating was measured using a non-contact thermal expansion measuring system in the temperature range from 25°C to 1500°C. The change in the crystal structure of the coating was also investigated by X-ray diffraction and differential thermal analysis. When first heated up to 1500°C, the Y2SiO5 coating showed irreversible expansion; small expansion at around 400°C and large expansion at about 1200°C. This irreversible expansion is attributable to crystallization of the Y2SiO5 coating, which changes from a dense randomly packed structrue as in the sprayed state to the B-type Y2SiO5 structure (space group: C2/c) as a stable state. The annealed Y2SiO5 coating showed no irreversible expansion and the thermal expansion coefficient of the coating was 6.5×10−6 °C−1. We suggest a new oxidation-resistant coating for use on C/C composites which consists of an inner SiC layer serving as an oxygen barrier and an outer refractory oxide layer for erosion protection. The Y2SiO5 coating is well-suited for use as the outer layer of out oxidation-resistant coating, because the degree of expansion of the annealed Y2SiO5 coating is close to that of the inner SiC layer.
  • 水本 将之, 花岡 剛史, 宮原 広郁, 大城 桂作
    1999 年 63 巻 10 号 p. 1304-1310
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    Directional solidification experiments have been carried out in continuous alumina fiber reinforced Al-4.5 and 15 mass%Cu alloy composites, to characterize dendrite tip undercooling and inter-dendrite spacing as functions of the copper content and the volume fraction of fiber. The position of the primary dendrite tip in the composite region is located 450∼750 μm below that in the bulk region. The dendrite tip temperature in the composite region is estimated to be 1.2 to 1.7 K lower than that in the bulk region, since the temperature gradient is 2.5 K/mm in the present work. The copper concentration (CS) at the dendrite tips in the composite region is higher by 0.05 to 0.15 mass% than that in the bulk region, and increases as the dendrite tip temperature becomes lower. The smaller the fiber interstice is, the higher the CS value. Furthermore, the primary dendrite arm spacing is smaller in the composite region. A model based on the continuity for liquid phase among fibers reveals how the fibers influence the copper concentration of the dendrite tip and the size of the lateral solute diffusion field.
  • 林 重成, 成田 敏夫
    1999 年 63 巻 10 号 p. 1311-1316
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    The internal oxidation and nitridation behavior of an Fe-5 mass%Al alloy was investigated at 1073 K in oxygen, nitrogen-20 vol%oxygen(mix), and air atmospheres for up to 57.6 ks using thermo-gravimetry, scanning electron microscope, electron probe micro analyzer, and X-ray diffraction analysis. The time dependence of the amount of oxidation showed very high oxidation rate at the initial stage, a transient stage with a rapid rate decrease, and then steady state oxidation. The critical times between the transient and steady states were 900 s in air, and 2 ks in both the mix and in O2. In the “steady state” condition, the oxidation rate in O2 was very slow, while it was relatively faster in the mix and in air. In O2, both a thin duplex (Fe2O3 and Al2O3) and a thick triplex (Fe2O3, Fe3O4, and FeAl2O4) scales formed and the film-like internal oxides grew beneath the thick triplex scale. In the mix and in air a thick scale formed with a triplex structure of Fe2O3, Fe3O4, and FeAl2O4 accompanied by an internal oxidation of duplex FeAl2O4 and Al2O3 zones, which grew perpendicularly to an alloy/scale interface, and spike-like AlN precipitates formed beneath the internal oxidation zone. Further, film-like Al2O3 formed locally at the top of internal AlN precipitates. A precipitate free zone (PFZ) formed between the internal oxidation and nitridation zone, and a formation mechanism for the PFZ was proposed.
  • 山本 恭永, 橋本 健紀, 木村 隆, 信木 稔, 河野 紀雄
    1999 年 63 巻 10 号 p. 1317-1326
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    Al-Ti-M (M=Mn, Cr, Ag) ternary alloys and Al-Ti-X-Y (X, Y=Mn, Cr, Ag, Fe) quaternary alloys were homogenized at 1450 K for 84.6 ks. The as-cast and homogenized specimens have been examined by laser optical microscopy, electron probe microanalysis (EPMA) and X-ray diffraction. In the quaternary system, the L12-type titanium trialuminide phases at 1450 K were confirmed in a composition region, where the composition of the L12-type phase changes continuously from the L12-type (AlX)3Ti ternary region to L12-type (AlY)3Ti ternary region, irrespective of the assorted element X and Y. After the survey of the L12-type single-phase composition in the quaternary systems, the single-phase domain was constructed in the quaternary composition diagrams. The domain exhibited a nearly ellipsoidal pipe through the L12-type (AlX)3Ti ternary region and the L12-type (AlY)3Ti ternary region for all X and Y elements considered. The amount of porosity in the homogenized quaternary alloys was larger than that in the cast alloys. The amount of porosity in the quaternary Al-Ti-Cr-Fe alloy was the smallest among the examined ternary and quaternary systems. When Ag was added into the L12-type (AlMn)3Ti or (AlCr)3Ti phases, the lattice parameter of the resultant L12-type phases increased. However, chromium addition to the L12-type (AlMn)3Ti phase did not change the lattice parameter. In the quaternary systems of Al-Ti-Mn-Fe and Al-Ti-Mn-Cr, the lattice parameter change of the L12-type phases with composition can not be explained from the atomic size effect.
  • 春名 匠, 山本 雅則, 柴田 俊夫
    1999 年 63 巻 10 号 p. 1327-1331
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    Environment-assisted cracking (EAC) of Ti in methanol solutions containing various concentrations of CaCl2 has been investigated by using a slow strain rate testing (SSRT) apparatus with dynamic observation system. In the EAC test, water content in the solutions was strictly controlled and the test solution was fully deaerated. Like the case of HCl addition, it was observed that cracks were initiated from black pits generating during the test and that the cracking mode was intergranular at the initial stage and transgranular at the final stage of the crack propagation. Under open circuit condition, cracking occurred only at 0.02 and 0.2 kmol·m−3 CaCl2 and the maximum corrosion potentials when cracking occurred, which means the critical potential for EAC, was a negative function of the logarithm of the chloride concentration. The potentiostatic SSRT confirmed the linear relationship between the critical potential and logarithm of chloride concentration in the chloride concentration range from 4×10−4 to 4×10−2 kmol·m−3. In comparison with the case of HCl addition, CaCl2 addition provided the same slope of the relation but higher critical potential. It was also found that the dissolved oxygen plays a role of increasing corrosion potential as an oxidant, and that the cracking occurs when the corrosion potential exceeds the critical value for EAC. It is concluded that the EAC initiation of this system is controlled by the mechanism of initiation of anodic localized corrosion by chloride ions.
  • 山下 正人, 米澤 泰輔, 内田 仁
    1999 年 63 巻 10 号 p. 1332-1337
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    The effects of ion species in electrolyte films covering a weathering steel surface on the rust formation and protective ability of the rust in a 3.5%NaCl solution have been examined. Scanning vibrating electrode measurements of corrosion current distributions at the steel surfaces, which are covered with various rust layers formed under the electrolyte thin layers mentioned above, in the NaCl solution, and the structural analyses of the rust layers show the following results. (1) Rust layer as mixture of β-FeOOH, γ-FeOOH and a small amount of α-FeOOH does not prevent metal dissolution. A large number of anode and cathode current peaks are observed. (2) The Cr-substituted goethite layer formed under the electrolyte containing Cr3+ and SO42− strongly suppresses metal dissolution in the NaCl solution, maybe due to the densely aggregated structure of fine particles of the goethite. (3) The rust layer formed under the electrolyte containing Ni2+ and SO42− also possesses high protective ability against corrosive Cl anion, probably due to an effect inactivating Cl in the rust layer as well as its aggregated structure of rust particles. These results indicate that the corrosion rate of steel is closely related to the rust phase and structure controlled by ion species in an electrolyte thin film.
  • 鄭 潤哲, 李 禎茂, 韓 承傳, 金 昌周
    1999 年 63 巻 10 号 p. 1338-1347
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    The effects of aging temperature and microstructure on the mechanical and physical properties of a Cu-9Ni-6Sn(mass%) alloy were investigated and the following results were obtained. The mechanical and physical properties such as tensile strength, elongation and electrical resistivity of the Cu-9Ni-6Sn alloy were strongly dependent on the aging temperature, aging time and microstructures. This alloy was much strengthened by aging at temperatures below 673 K where the spinodal decomposition occurs, but the specimen is not strengthened by aging at temperatures above 673 K where the discontinuous precipitate forms. The electrical resistivity was decreased by aging and the degree of reduction increased with increasing aging temperature and time. These results obtained in the present study indicate that the strengthening mechanisms of the Cu-9Ni-6Sn alloy are changed by the aging conditions.
  • 坂本 佳紀, 梶田 伸彦, 佐貫 須美子, 前 健彦, 能登谷 久公, 新井 甲一
    1999 年 63 巻 10 号 p. 1348-1355
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    The optimum Ni content in the modified 5052 alloy by electron beam alloying was investigated based on the measurement of the mechanical strength of the modified 5052 alloys and the strength of the interface between the substrate and the modified alloys. The X-ray diffraction or EDX analysis of the precipitates, the scanning electron microscopic observations of the samples with or without modification and the fracture surfaces after tensile tests were also performed.
    The main results obtained are summarized as follows:
    (1) Three types of structures were observed in the modified 5052 alloys: fine Al(α) grain, Al(α)+Al3Ni(β), and coarse Al3Ni(β) intermetallic particles. The surface area ratio of the Al+Al3Ni(β) eutectic structure increases with increasing Ni contents below 8 mass%, whereas the ratio decreases at Ni contents higher than 8 mass%. Furthermore, the surface area ratio of the large size Al3Ni intermetallic compound increases with increasing Ni content. (2) The Vickers hardness of the modified alloys increases with increasing Ni content in the alloy. The mechanical strength such as the U.T.S. of the modified alloys increases with increasing Ni content below 5 mass% and the values of 300 MPa is almost constant at Ni contents from 5 mass% to 8 mass%. However, the values of the U.T.S. were reduced when the Ni content was over 8 mass%. The mechanical strength of the interface between the substrate and the modified area is stronger in comparison with that of the substrate alloy. (3) Fracture cracking initialtion is observed around the coarse Al3Ni(β) intermetallic particles. Based on the examined data, the optimum Ni content in the modified 5052 alloy was determined to be 5 to 8 mass%.
  • 中江 秀雄, 加藤 弘之
    1999 年 63 巻 10 号 p. 1356-1362
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    Wetting phenomenon has been discussed on the basis of the energy balance among solids, liquids and vapors. In these discussions, many researchers have dealt with the surface energy value as an intrinsic parameter. But the extrinsic one, which is changed by the vapor of the liquid, should be used. In this paper we discussed the change in the solid surface energy of solid-Si in the Si/Al-Si systems for equilibrium wetting and nonequilibrium wetting using the sessile drop method. The final objective of this research is the solution of the modification mechanism of Si in Al-Si alloys. The experimental results are as follows;
    1. The surface free energy of Si decreases much due to the Al vapor, but the decrease is less at the (111) face than at the other faces.
    2. The decreasing rate in Si/Al-Si-Sr systems is much higher than in the Si/Al-Si systems.
    3. These phenomena can be recognized by the change in the contact angles with time for the Si/Al-Si and Al-Si-Sr equilibrium systems.
  • 永山 勝久, 宮入 哲, 菅原 裕明
    1999 年 63 巻 10 号 p. 1363-1364
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    We examined the undercooling behavior and bulk state amorphous formation of a drop-like Pd40Cu30Ni10P20 alloy using the high frequency heating and melting apparatus by 1 kW power supply. In view of the high undercooling liquid formation ability of the above alloy, we used a combination of two solidification processes: the slow cooling solidification until just before nucleation temperature in vacuum atomosphere and just after He gas jet cooling. As a result, we have shown the undercooling solidification and the newly bulk state amorphous formation process of Pd40Cu30Ni10P20 alloy in detail.
  • 春名 匠, 大西 浩三, 柴田 俊夫
    1999 年 63 巻 10 号 p. 1365-1366
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    Effect of irradiation by ultra-violet(UV) light on stress corrosion cracking(SCC) of sensitized SUS304 stainless steel in a deaerated 10−3 kmol·m−3 NaCl solution has been investigated by using a slow strain rate testing (SSRT) apparatus with a dynamic observation system. The SCC initiation was inhibited by the UV light irradiation to the specimen during SSRT. Change in the light intensity led to the change in crack initiation frequency. The maximum inhibition effect was observed at an optimum intensity. However, crack propagation rate showed almost no significant dependence on any irradiation conditions.
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