巻号一覧
70 巻, 2 号
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松田 賢士, 水平 学, 山本 信雄2006 年 70 巻 2 号 p. 107-109
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーA quick, easy and highly sensitive analysis of toxic metals has been required for a purpose of WEEE and RoHS directive. 3-dimensional polarization optics energy dispersive X-Ray fluorescence spectrometer (3D-EDX, Epsilon5, PANalytical B.V.) has been introduced as a easy and accurate with high sensitive method for bulk samples. To adapt this measurement method to shaped Brass samples, the scatter collection was used. Intensities of each element lines (Ka for Cr, Cd and Lb for Pb) have been collected by Rayleigh scatter of each secondary targets these are used for exciting interesting elements. Calibration curves were created and obtained by CRM's bulk flat Brass standard samples for Cr, Cd, and Pb. Estimated LLD (Lower Limit of Detection) was Cd 3.28 μg/g, Pb 29.0 μg/g, and Cr 6.64 μg/g with 300 seconds measurement time for each condition. Cd and Pb of some shaped and small Brass samples, they have been quantified by ICP-AES, were measured and quantified by Rayleigh scatter collection. As a result of this comparison, there are quite good correlation between ICP-AES and Epsilon5 with Rayleigh scatter correction. This correlation was also valid for smaller samples (e.g. 5 mg sample weight for Pb measurement). These LLD were kept while measurement was done within Maximum operating power (600 W, 100 kV, 6 mA).
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竹元 嘉利, 清水 一郎, 榊原 精, 瀬沼 武秀2006 年 70 巻 2 号 p. 110-113
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーThe aim of this study is to systematically investigate the elastic behavior with deformation of the binary titanium alloys of Ti-Mo, Ti-Nb and Ti-V. The stress-strain curve using cyclic load-unloading tensile test of alloys composed of α″ martensite, e.g. 20Nb and 8Mo, showed the peculiar pseudo-elastic behavior. A little higher content of β-stabilizer alloys of 38Nb, 10-14Mo and 15-20V, which were composed of β and commensurate ω phases by quench, indicated the liner elasticity until the yield but changed to the extreme pseudo-elasticity after {332}<113> twin formation. Dynamic observation made clear certain {332}<113> twin initially formed on tensile loading disappeared during unloading process. Medium content of β-stabilizer alloys of 42Nb and 16Mo exhibited a concave downward elastic curve and were deformed by mixture mode of slip and {332}<113> twin. On the higher content alloys it was found that the stress level on which Young's modulus begins a rise increases with the increase of alloy content. These elastic features were summarized as change of apparent Young's modulus with increase of strain.
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醍醐 市朗, 松野 泰也, 足立 芳寛2006 年 70 巻 2 号 p. 114-117
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーSome post-consumer products are not collected appropriately and are remained or disposed by unconventional methods. In order to conserve resources, the collection ratio of such products should be increased. To date, few definitive methods to quantify the collection ratio have been developed because the amount of dissipative products cannot be measured. In this paper, a new statistical method was developed to quantify the collection ratio of post-consumer products. This method is based on the identification of dynamic material flow of steel used in such products. The collection ratios of buildings, constructions, and machines were estimated. The amount of discarded post-consumer products during a year was calculated dynamically from their lifetime distributions and production history in which steel was used prior to that year. Uncertainty derived from the lifetime distributions was considered in the calculations. Finally, the collection ratios of the products were obtained with uncertainty as 1.00 (buildings), 0.00-0.22 (constructions), and 0.39-0.53 (machines).
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宍戸 逸朗, 松尾 明彦, 豊山 裕万, 水野 正隆, 荒木 秀樹, 白井 泰治2006 年 70 巻 2 号 p. 118-121
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーThe influence of plating additives on lattice defects in electrolytic copper made with various amount of plating additives has been investigated by positron annihilation technique. The results show that the copper plated with no leveler and normal amount of brightener includes vacancy clusters corresponding to positron lifetime of about 330 ps. On the other hand, the other samples have no remarkable vacancy clusters. These suggest that plating additives influence not only on the copper surface morphology but also on the formation of the microscopic lattice defects.
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西村 雅俊, 徳永 辰也, 大谷 博司, 長谷部 光弘2006 年 70 巻 2 号 p. 122-125
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーPhase equilibria in the Be-Ti-V ternary system have been calculated using a thermodynamic description of the constituent binary systems. Energetic values obtained from first-principles calculations were utilized in our thermodynamic analysis to compensate for the lack of experimental data on the Be-V system. The thermodynamic treatment of the Be-Ti and Ti-V systems was based on previous assessments, and no additional ternary thermodynamic parameter was introduced. Our calculations show that a metastable two-phase separation of the bcc phase is present in the V-rich region of the Be-V binary system, and that this two-phase separation is stabilized in the Be-Ti-V ternary system. Furthermore, the metastable Be-Ti based binary B2 phase was also stable in the ternary system, and it participates in the phase equilibria over a wide composition range.
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室 昌孝, 宮澤 俊輔, 竹中 俊英, 川上 正博2006 年 70 巻 2 号 p. 126-129
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーThe dependence of Ti alloy coating by using a disproportionation reaction in molten chloride upon the coating conditions has been investigated. The corrosion resistance of the coated specimen was also examined. An equimolar NaCl-KCl mixture was melted in a quartz crucible under the atmosphere of high-purity Ar, and TiCl3 was added with Ti sponge into the mixture. Iron, carbon steel, Ni and stainless steel plates were immersed in the bath at 1100~1250 K for a scheduled period. After the immersion, the Fe plate was covered with a dense layer of Ti-Fe alloy of which thickness was more than 10 μm. The layer adhered to the surface, and mainly consisted of Fe2Ti. Carbon steel was covered with a similar Ti-Fe layer to that on the Fe plate, and carbides were not found. The surface of the Ni plate was fully covered with NiTi2, and a dense layer of Ni3Ti was formed under the NiTi2 layer. The Ti alloy layer on Ni was thicker than those on Fe and carbon steel under the same condition. A dense layer of a few μm, where Ti content was about 90 mass%, was observed on the surface of the stainless steel plate after the immersion. The thickness of the Ti alloy layer was in proportion to the square root of the immersion time, and its formation rate was not affected very much by the initial TiCl3 concentration. These results indicated that the formation rate of Ti alloy layer was mainly controlled by the diffusion of elements in the formed layer. The corrosion resistance of Fe and carbon steel against salt water was significantly improved by the Ti alloy coating on the surface.
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中田 隼矢, 駒崎 慎一, 幸野 豊, 芝 清之, 香山 晃, 橋田 俊之2006 年 70 巻 2 号 p. 130-133
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーReduced activation ferritic/martensitic steels (RAFs) are leading candidates for structural materials of fusion reactors. It is essential to understand an influence of irradiation on their mechanical properties such as impact toughness and creep properties to put them in practical use. However, since there are severe limitations on specimen capacity at material irradiation testing facilities, it is required to use miniaturized specimens.
In this paper, creep properties of the RAFs, JLF-1 and F82H were evaluated by recently developed small punch (SP) creep test. The test results were correlated with those of standard uniaxial creep test in terms of the conversion of applied load to stress. Experimental results revealed that the relationship between minimum creep deflection rate and rupture life measured by the SP creep test followed the Monkman-Grant's low as well as those of uniaxial test. The rupture lives of uniaxial and SP tests were arranged against the applied stress and load using Larson-Miller parameter, respectively. Then, the ratio of load (F, N) to stress (σ, MPa) was calculated so that both curves were overlapped each other. As a result, the correlation was estimated to be F=2.4σ and was consistent with that reported in the conventional CrMoV casting steel.
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村上 浩二, 水戸岡 豊, 日野 実, 五百川 晴義, 小野 裕行, 片山 聖二2006 年 70 巻 2 号 p. 134-137
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーHybrid welding by laser (YAG, 2.7 kW) and arc (TIG, 300 A) was studied for rapid welding on two 90°-bent sheets which face each other of 800 MPa-class high tensile strength steel in automotive applications. In the case the TIG torch preceded the laser irradiation, the arc generated between the tungsten electrode and the steel sheet became unstable because of its elongation by the feed of the molten pool, on which the arc tends to stay, and its sudden transfer to the steel sheet in the proximity of the tungsten electrode. On the other hand, higher stability of the arc and the resulting uniform beads were obtained when the TIG torch followed the laser irradiation. Microstructure and hardness of the welded region varied corresponding to the feed speed of the steel sheets. The heavier feed (117 mm/s) resulted in higher hardness in the bead, and hardness suddenly dropped in the heat-affected zone in comparison with the case of the lighter feed (50 mm/s). Since worked areas containing dislocations undergoes recovery as well as martensite, bainite, and pearlite transformations during welding and subsequent cooling, nonuniformity of the welded part arises especially in the rapid fabrication by hybrid welding. Heat input, expansion of the heat-affected zone, and resulting microstructure must be appropriately tuned depending on the size and the shape of the product for assuring desired mechanical properties.
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東雲 秀司, 宇都野 正史, 永山 勝久2006 年 70 巻 2 号 p. 138-141
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーFor Rare Earth-Transition Metal-Al with high undercooled liquid formability and glass-forming ability, bulk alloys have been produced with gas jet flow type electromagnetic levitation process, which is a new containerless process. A series of alloys of La80-xCu10Ni5Co5Alx (x=15, 20, 25 at%) were analyzed with respects to the supercooled solidification process, nucleation behavior of a crystalline phase, and the possibility of the formation of bulk amorphous alloys. In addition, the similar studies were carried out for the specimens containing SiC, which is reported to be effective to enlarge undercooling when used in the containerless process. The results show that the addition of SiC suppresses the nucleation of a crystalline phase, and thus, the undercooling (ΔT) increases in the range of ΔT=0.22 to 0.28 Tm, where Tm is the melting point. In addition, partially crystallized bulk amorphous alloys with a diameter of 6 mm are obtainable for the alloys with 0.2 mass% SiC addition when they are solidified at approximate cooling rate of 100 K/s. Furthermore, the SiC free alloys of La65Cu10Ni5Co5Al15 and Nd60Fe20Co10Al10 are also obtainable as partially crystallized bulk amorphous alloys.
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沼田 泰子, 首藤 文榮, 野村 直之, 千葉 晶彦2006 年 70 巻 2 号 p. 142-145
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーWe evaluated the biocompatibility of cobalt-29 chromium-6 molybdenum alloy by analyzing disorders of the membranes of cells of the murine fibroblast L929 line. L929 cells were incubated with 10% fetal bovine serum at 37°C for 7 days in Eagle's minimum essential medium in the presence of either an extract of this alloy, or titanium extract, or vanadium ions. No morphological changes in the cells were observed in medium containing cobalt-29 chromium-6 molybdenum alloy extract or titanium extract, but a remarkable change was observed in the medium containing vanadium ion as a positive control. From the enzyme activity of the culture supernatant we determined the amount of lactate dehydrogenase (LDH) that leaked through the cell membranes. The amount that leaked from cells incubated in the presence of either of the metal extracts or vanadium ion decreased on day 1 and then increased with incubation time from day 2 onward. There was only a small increase in leakage in the media containing the metal extracts but a marked increase in the medium containing vanadium ion. These results indicate that the cell membrane remained nearly unaffected by Co-29Cr-6Mo alloy.
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筑井 則行, 古畑 肇, 和田 光司, 大橋 修2006 年 70 巻 2 号 p. 146-149
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーRecent reports on sintering and bonding using the pulsed electric current bonding process indicate that the metals experience Joule heating due to electrical resistance at points of contact. However the detailed influence of the electric current wave on local heating phenomena remains unclear. In this study, to clearly isolate the effects of the characteristics of the current wave (frequency, duty ratio and power) in pulsed current bonding, joints of SUS304 stainless steel were formed under a variety of conditions.
It was found that the local heating efficiency at the bonded interface is high in the initial bonding stage and the temperature gradient in the bonded zone is steep. With a longer bonding duration the gradient becomes small. The frequency and duty ratio of the electric current wave do not influence local heating phenomena. When the electrical power is high, local heating at the contact area is accelerated. Direct current delivers greater power than pulsed current, and heats the contact zone more efficiently than the pulsed current.
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石山 宜寿, 黛 正己, 大中 健太郎, 谷 純一2006 年 70 巻 2 号 p. 150-153
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーRecently, stress corrosion cracking (SCC) was observed in lots of Japanese BWR plant components made of L grade stainless steel (SS) with very low carbon content. SCC essentially has a probabilistic nature, thus the probabilistic analysis is necessary to better understand SCC behavior and establish countermeasures. However, no experimental study was made for these SCC observed on non-sensitized SS from such a probabilistic aspect.
SCC test was conducted by the creviced bent beam (CBB) method in high temperature water containing 8 ppm dissolved oxygen. The test specimen was used in as-received and 10% cold rolled conditions. To examine the probabilistic aspect of SCC, 10 specimens were used for each test condition. The test duration were set to 500 h and 1000 h. After the test, the specimen surface and the fracture surface were observed by scanning electron microscopy to count the number of cracks and measure the crack length and depth.
From the results, it was found that the distribution of SCC crack lengths conformed to the log-normal distribution for type 316L and type 316SS irrespective of the pre-treatment and material conditions. On the other hand, the distribution of SCC crack depths conformed to both the normal and log-normal distribution.
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小林 敏郎, 小川 真, 中野 要治, 田口 俊夫, 神川 進, 伊藤 義文2006 年 70 巻 2 号 p. 154-157
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーSiOx thin films were vacuum deposited on a 25 μm thick PET substrate under various conditions. The effects of the chamber pressure, evaporating temperature, and deposited film thickness on the oxygen transmission rate (OTR) were investigated. The results were:
(1) The lower the chamber pressure and the higher the evaporating temperature, the lower the OTR is except the chamber pressure of 1.3×10-2 Pa or lower.
(2) Specimens having high OTR show high O/Si atomic ratio. It is suggested that deposited SiOx films of these specimens are porous or have a large surface area, so that a greater amount of SiOx is oxidized to SiO2.
(3) UV irradiation decreased OTR from 0.056 to 0.009 pmol/m2•s•Pa with chamber pressure 6.6×10-2 Pa and evaporating temperature 1530 K. The reason suggested for this is activation and cleaning of the substrate and depositing surface.
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早川 博, 榎 浩利, 秋葉 悦男2006 年 70 巻 2 号 p. 158-161
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーIn La-Mg-Ni system hydrogen storage alloys, which have been attracting attention as a promising negative electrode material for Ni-MH secondary batteries, there are many phases with a variously layered stacking structure. When subjected to annealing at high temperature, the composition of these alloys becomes inhomogeneous due to the volatilization of Mg. It is therefore difficult to prepare a single phase by the normal annealing procedure. We carried out high-temperature annealing processing in which we controlled the Mg vapor pressure of La4MgNi19 alloy using a temperature-gradient furnace. By controlling the Mg vapor pressure under the sealing atmosphere, we successfully obtained homogeneous La4MgNi19. We prepared a PMg-T diagram of the phases formed for La4MgNi19 composition, and found the optimum annealing conditions for the La4MgNi19 phase. The optimum annealing conditions obtained were between T=1123 K, PMg=0.4 kPa and T=1223 K, PMg=2 kPa. However, we found the coexistence of 3R-type and 2H-type structures, which are polytypes of La4MgNi19. The lattice constants of the 3R type were a=0.5031 nm, c=4.826 nm, and those of the 2H type were a=0.5032 nm, c=3.216 nm. The hydrogen storage characteristics of the annealed alloy were obtained by measuring the PCT curves at 333 K. The PCT curves showed an almost flat plateau, PH2=0.1 MPa, H/M=1.1, 1.5 mass%H2, and good cycle characteristics. It was confirmed that the dehydrogenated alloy retained the same structure but an expansion of 1 to 2% was observed in the c-axis.
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山口 正彦, 市坪 哲, 松原 英一郎, 木村 久道, 笹森 賢一郎, 入江 久夫, 隈元 聖史, 穴田 隆昭2006 年 70 巻 2 号 p. 162-165
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーSn-Zn based solder alloys are expected to be a potential candidate as a lead-free low temperature solder because of its melting point close to that of Sn-Pb. There are, however, several problems in practical application. Cu-Zn intermetallic compound (IMC) layer formed at the solder and Cu substrate interface leads to degradation of adhesion strength. In order to prevent the formation of Cu-Zn IMC, we have added some additives (Ni and Cu) to the Sn-Zn solders. We have also investigated the quenching effect by the atomization process in these Sn-Zn-(Ni and Cu) solders. For the pre-atomized solders, Cu-Zn IMC layer is formed at the interface. On the other hand, for the atomized solders, Cu-Sn IMC layer which is usually seen in Sn-Pb solder is observed instead.
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増田 進吾, 松村 義人, 西 義武2006 年 70 巻 2 号 p. 166-168
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーComposite mover device constructed with both negative and positive magnetostrictive thin films on each side surface of silicon substrate were prepared by DC magnetron sputtering process. The magnetic field induced mover strain (an apparent magnetostriction) of composite mover device at 150 kA/m of magnetic field was as same as the sum of magnetostriction values of Sm-Fe negative and Tb-Fe positive magnetostrictive thin films. Although the magnetostrictive susceptibility of Sm-Fe negative and Tb-Fe positive magnetostrictive thin films were over 8.6 and 5.42 ppm/kA•m-1, respectively, an apparent magnetostrictive susceptibility of the composite mover device was 36.4 ppm/kA•m-1. We concluded that composite process tremendously enhanced the apparent magnetostrictive susceptibility. Composite mover device with high responsiveness was developed.
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栃澤 まどか, 小栗 和也, 鈴木 恒則, 西 義武, 長田 純佳, 井上 徳之2006 年 70 巻 2 号 p. 169-172
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーA Science Partnership Program (SPP) for junior high school students was planned by a university and a science museum (Miraikan). To improve students' interest in science and technology, a total of five lessons are performed by researchers with three SEM observation lessons, and two presentation lessons. SEM samples are prepared and selected by students after optical microscope observations. As a result, students become familiar with science. It also increased their interest in science and technology and in researchers' work. Public Understanding of Research (PUR) is required of researchers. This program will serve as a good example in creating collaboration programs for schools with universities, institutes, societies and science museums. A science museum will be a key coordinator for these collaboration programs.
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鈴木 崇宣, 横川 忠晴, 小林 敏治, 原田 広史, 今井 八郎2006 年 70 巻 2 号 p. 173-175
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーEffect of Cobalt on micro-structural parameters, such as the lattice misfit and partitioning behaviors of alloying elements, of Re-bearing Ni-base single crystal superalloys have been investigated. The second-generation single crystal superalloys, TMS-82+(Ni-7.8Co-4.9Cr-1.9Mo-8.7W-5.3Al-6.0Ta-2.4Re-0.1Hf, in mass%), was compared to a Co-free (0Co) alloy which had the same chemical composition as TMS-82+ except that Co was removed.
The lattice misfit of 0Co alloy was found to be more negative value than that of TMS-82+ at any temperature. Additionally, when 0Co alloy was equilibrated at 1100°C, Cr, Mo and W partitioned more into the γ matrix; in contrast, Al and Ti partitioned into the γ′ precipitates. Increase in partitioning of Cr, Mo and W to the γ phase resulted in an increase in the lattice parameter of γ phase. Thus, lattice misfit of 0Co tend to more negative value than that of TMS-82+.
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小泉 裕, 横川 忠晴, 原田 広史, 小林 敏治2006 年 70 巻 2 号 p. 176-179
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーMany Ni-base single crystal superalloys were developed as a structural material in the hot sections of the jet engine, etc. However, relative comparison of their mechanical properties is usually difficult, due to the difference of the manufacturing processes and the test conditions. Then, we have tried to make the database of the creep properties obtained on as same manufacturing process and testing condition as possible for commercial alloys.
In this study, the creep rupture tests were examined for RenéN4, RenéN5 and CMSX-4 SC alloys, which were cast by using our directionally solidified casting furnace. The temperature/stress conditions of the creep tests were settled in the range from 900°C to 1100°C and, from 137 to 392 MPa. It is cleared that the creep strengths of RenéN5 and CMSX-4 are exceeded RenéN4 in all testing conditions. In addition, the rupture life of CMSX-4 at higher temperature/lower stress condition in this study is longer than the reported life in published papers.
All creep properties obtained from this study are added to the database, and are not only used for the turbine design but also for the virtual jet engine computer simulation program.
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佐藤 敦史, 原田 広史, 小泉 裕, 小林 敏治, 川岸 京子, 今井 八郎2006 年 70 巻 2 号 p. 180-183
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーImprovement of the oxidation resistance of a 5th generation nickel-base single crystal (SC) superalloy through the addition of silicon was attempted. A 5th generation nickel-base SC superalloy TMS-173 (5.6Co-2.8Cr-2.8Mo-5.6W-5.6Al-5.6Ta-0.1Hf-6.9Re-5.0Ru (Ni-bal. mass%)) has excellent creep properties. This was accomplished by increasing the ruthenium content to accommodate the increased amount of rhenium, an element that improves high temperature properties. On the other hand, their additions decrease oxidation resistance.
In this study, silicon was added to modify the oxidation property. However, TMS-173 alloy contains saturated amounts of solution strengthening elements in γ/γ′; therefore, in order to add silicon, tantalum was substituted out to maintain γ/γ′ microstructure. A 50-Cycle oxidation test at 1100°C was carried out to evaluate the effects of silicon, with each cycle lasting one hour. SEM and EDX were used for cross-section analysis.
TMS-173-Ta+Si (5.8Co-2.9Cr-2.9Mo-5.8W-5.8Al-0.1Hf-7.2Re-5.2Ru-1.9Si (Ni-bal. mass%)), showed excellent oxidation resistance; weight loss was much less than that of Rene'N5, and the oxide layer formed was exclusively Al2O3.
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北嶋 具教, 平 徳 海, 原田 広史, 小林 敏治2006 年 70 巻 2 号 p. 184-187
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーThe precipitation of topologically-closed-packed (TCP) phases in Ni-base single crystal superalloys was suppressed due to the Ruthenium or Iridium additions, resulting in the superior creep resistance. However, no clear explanation for such improvement in phase stability has been reported. Therefore, it's necessary to determine the underlying mechanism in the atomic scale such as short range ordering and elemental distributions in the gamma phase. The present article has investigated the effects of Ru/Ir additions on elemental distributions in gamma phase by using 3-dimensional atom probe field-ion microscopy.
The concentration frequencies of Re, W and Mo within Ru/Ir centered spheres including 100 atoms in gamma phases were analyzed statistically. The results showed that the concentration frequencies of Re, W and Mo within Ru/Ir centered spheres corresponded to binomial distributions. This indicated that the effects of Ru/Ir additions on elemental distributions in the gamma phase were not able to be detected under the condition employed in the present study.
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川岸 京子, 佐藤 彰洋, 原田 広史2006 年 70 巻 2 号 p. 188-191
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーA new and stable bond coat system, EQ coating, which is in equilibrium thermodynamically with γ/γ′ substrate, suppresses the diffusion of alloying elements between the substrate and coating, and the formation of SRZ. In this study, β phase is proposed as the candidate for oxidation-resistant EQ coating material because of its high Al content. Combinations of γ/γ′ alloy for the substrate material and β alloy for the coating material which are in equilibrium were developed in Ni-Al-Cr ternary system and Ni-base multi-component system. Diffusion couples were made for each combination and were heat treated at 1100°C for 300 h. The concentration profiles of the alloying elements at the interfaces between the β alloy and γ/γ′ alloy in the diffusion couples were analyzed to investigate the existence of the diffusion zone. Cyclic oxidation examination was performed and oxidation properties were discussed.
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佐藤 彰洋, 原田 広史, 川岸 京子2006 年 70 巻 2 号 p. 192-195
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーAdvanced Ni-base single crystal (SC) superalloys containing high concentrations of refractory elements prone to generate a diffusion layer called Secondary Reaction Zone (SRZ) beneath their bond coating during exposure at high temperatures. SRZ cause a reduction of the load bearing cross section and it is detrimental to the creep properties of thin-wall turbine airfoils.
In this study, a new bond coat system “EQ coating” designed to be in thermodynamic equilibrium with the Ni-based superalloy substrate has been proposed. Two types of EQ coating systems based on γ and γ′ compositions on the tie line of the base alloy (TMS-82+ or TMS-173) were studied and compared with a conventional bond coat. Each coating system was diffusion coupled with the substrate material and subjected to isothermal exposure at 1100°C for 300 hours. The results have indicated minimal interdiffusion occurred between EQ coating systems and the substrate. The EQ coating based on γ′ composition possesses the most promising oxidation resistance.
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佐藤 彰洋, 原田 広史, 小林 敏治, 村雲 岳郎, 張 建 新, 横川 忠晴2006 年 70 巻 2 号 p. 196-199
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーThe National Institute of Materials Science (NIMS) has utilized the in-house alloy design program to develop a 5th generation Ni-base single crystal superalloy, TMS-196 with superior high temperature creep and oxidation resistance by incorporating further ruthenium (Ru) and chromium (Cr) content over the compositions of 4th generation superalloys. With Ru additions in advanced superalloys to enhance phase stability, higher content of refractory elements can be accommodated to provide further strengthening; the associated oxidation resistance can be improved by the increase in Cr additions.
In present article, TMS-196 has been subjected to cyclic/isothermal oxidation tests at 1100°C and creep at conditions between 800°C~1100°C/137 MPa~735 MPa. Preliminary studies indicate that the surface of oxidized TMS-196 can exhibit continuous alumina layer attributing good oxidation resistance similar to that of Rene'N5. Detailed TEM analyses have shown the alloy system of TMS-196 possessing strong resistance to γ′ deformation during creep deformation. Data regarding to oxidation and creep properties of some previous generations of superalloys are also included for comparisons and discussions in this research.
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伊津野 仁史, 横川 忠晴, 原田 広史2006 年 70 巻 2 号 p. 200-203
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーWe have proposed a new creep constitutive equation for Ni-base superalloys with good reproductibility and predictivity of various temperature-stress conditions. In this paper, a direct prediction of creep curves from alloy compositions, structural parameters and temperature-stress condition is reported. For each of testing conditions, 1100°C/137 MPa, 1000°C/245 MPa, 900°C/392 MPa, 10 to 20 kinds of creep curves are fitted, and multi-regression analysis for each parameter of creep constitutive equation are made with gamma-prime composition, lattice misfit, volume fraction. For each parameter of the regression equation obtained from these multi-regression analysis, a regression with temperature is carried out. The result gives a good predictivity for any creep curves, especcialy in interpolation.
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中東 潤, 高畑 公輔, 鶴 健太郎, 住本 晃史, 吉村 博文, 堀村 弘幸2006 年 70 巻 2 号 p. 204-211
発行日: 2006年
公開日: 2006/02/24
ジャーナル フリーHydrogen treatment is one of the few possible methods for producing a fine-grain size of 0.3 to 0.5 μm in α+β Ti-6Al-4V alloys. The process of hydrogen treatment involves hydrogen absorption, quenching, hot rolling and hydrogen desorption. However, ultra-fine grain refinement of other titanium materials by this treatment has not yet been examined. In this study, the optimum hydrogen treatment conditions for ultra-fine grain refinement of two phase α+β Ti-3Al-2.5V, two phase α+β Ti-1Fe-0.35O and single phase α titanium were investigated in order to expand the application of this effective treatment to the grain refinement of other titanium materials. Tensile tests were also carried out at room and high temperatures to investigate the tensile properties of the grain-refined materials. The experimental results that were obtained are as follows.
An ultra-fine grain size in the range of 0.5 to 1 μm was produced in the Ti-3Al-2.5V and Ti-1Fe-0.35O alloys by controlling the hydrogen treatment conditions, particularly the content of hydrogen absorbed and hot rolling conditions. However, ultra-fine grain refinement of pure titanium was not observed. It is thought that one of the reasons for this lies with the differences in the morphology of the martensite obtained when quenching Ti-3Al-2.5V and Ti-1Fe-0.35O alloys. The proof stress of the ultra-fine-grained Ti-3Al-2.5V and Ti-1Fe-0.35O alloys was improved by the hydrogen treatment. According to the tensile tests carried out at 1098 K, ultra-fine-grained Ti-3Al-2.5V exhibited very large elongations of more than 9000%.
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