THE JAPANESE SWORD
The Material, Manufacturing and Computer Simulation of Quenching Process
Tatsuo INOUE
Review Paper (Vol.3 No.4)
THE JAPANESE SWORD |
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Tatsuo INOUE |
193 |
General Papers (Vol.3 No.4)
EFFECTS OF PRESSURE AND TEMPERATURE ON THE VISCOSITY B COEFFICIENT FOR POTASSIUM CHLORIDE IN WATER |
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Takehiro NAKAI, Seiji SAWAMURA, Yoshihiro TANIGUCHI and Takashi KUBOYAMA |
204 |
FORMATION AND MICROSTRACTURE OF SiO2-TiO2-ZrO2 GELS |
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Anucha WANNAGON, Naofumi MISHIMA, Rikuo OTA, Takashi WAKASUGI and Jiro FUKUNAGA |
210 |
A STUDY ON SNOW STICKING WEIGHT TO WATER-REPELENT COATINGS |
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Hiroyuki SAITO, Ken-ichi TAKAI, Hisayoshi TAKAZAWA and Goro YAMAGUCHI |
216 |
HEAT TREATMENT EFFECT ON TRANSFORMATION PROPERTIES OF TiNi SHAPE MEMORY ALLOY FILM |
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Sotohiro TAKABAYASHI, Katsumi TANINO and Kazuo KITAGAWA |
220 |
MOLECULAR DYNAMICS SIMULATION OF THE INFLUENCE OF CRYSTAL IMPERFECTION ON NANO-MACHINING MECHANISM |
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Katsuhiro MAEKAWA |
225 |
FET-BASED HOMOGENIZATION ALGORIYHM USING DIGITAI IMAGES |
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Kenjiro TERADA, Katsuyuki SUZUKI and Hideomi OHTSUBO |
231 |
CREEP LIFE ASSESSMENT OF 2.25Cr|1Mo PIPING STEEL AND OF ITS SIMVLATED HAZ MATERIAL |
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Kazunari FUJIYAMA, Takashi ISEKI, Atsushi KOMATSU and Nagatoshi OKABE |
237 |
CORROSION/DEFORMATION INTERACTIONS IN URANIUM/WATER SYSTEMS |
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Arie BUSSIBA, Henry ALUSH and Yosef KATZ |
244 |
PHYSICAL PROPERTIES VARIATION OF CORROSIVE REINFORCEMENT DUE TO S0DIUM CHLORIDE ATACK |
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Yoshinobu KOIBUCHI and Kiyoshi KATO |
252 |
Short comunication (Vol.3 No.4)
FORMATION AND CHARACTERIZATION OF STOICHIOMETRIV MULLITE(3Al203E2SiO2) PREPARED BY THE HYDRAZINE METHOD | |
Msayuki IMOSE, Masaru YOSHINAKA, Ken HIROTA and Oosamu YAMAGUCHI |
258 |
Vol.3 No.4 ABSTRACT
THE JAPANESE SWORD
The Material, Manufacturing and Computer Simulation of Quenching Process
Tatsuo INOUE
Abstract:Traditional methods of preparing a kind of steel called tamahagane used for the Japanese sword by tatara system and procedure of making the sword are briefly introduced with the discussions from the view point of metallurgy and thermo|mechanical processing. Such traditional methods are also revealed to be consistent with the modern science and technology. The quenching process applied to the final stage of the procedure is focussed to explain how the p at tern of blade, the deform at ion and residual stresses are induced by the computer simulation based on the theory of metallo-thermo-mechanics relevant to the coupled fields among temperature, microstructural change and stress/strain. Key Words:Japanese sword, Quenching, Metallo-thermo-mechanics, Tatara system, Tamahagane, Iron sand, Sori, Hamon
EFFECTS OF PRESSURE AND TEMPERATURE ON THE VISCOSITY B COEFFICIENT FOR POTASSIUM CHLORIDE IN WATER
Takehiro NAKAI, Seiji SAWAMURA, Yoshihiro TANIGUCHI and Takashi KUBOYAMA
Abstract:Viscosity of aqueous potassium chloride(KCl) solution was measured at temperature 283.2 and 323.2 K and pressure up to 375 Mpa by means of a rolling-ball viscometer. The Jones-Dole B coefficient of KCl at both temperatures increased with increasing pressure and then decreased after passing over maximum as well as previously observed one at 298. 2 K. The maximum became more pronounced at lower temperatures. In comparison with the dielectric friction theory, the observation of the maximum is ascribed to a balance between two contributions; pressure breaks any water structure (B increases) and reduces the dielectric friction between ion and solvent (B decreases). The temperature coefficient İB/İT was observed to be positive at all pressures and decreases with increasing pressure. The fact suggests that the structure-breaking effect or KCl for water reduces with increasing pressure, and the reduction of the effect may be ascribed that the water structure which should be broken by addition of the electrolyte is already broken by pressure. Key Words:Viscosity, Potassium chloride, Aqueous solution, Jones-Dole B coefficient, High pressure
FORMATION AND MICROSTRACTURE OF SiO2-TiO2-ZrO2 GELS
Anucha WANNAGON, Naofumi MISHIMA, Rikuo OTA, Takashi WAKASUGI and Jiro FUKUNAGA
Abstract:Gels were formed in the SiO2-TiO2-ZrO2 system. All of them were amorphous by XRD analysis, even though opaque gels were formed in the compositions range more than 80 mol% TiO2 and 60 mol% ZrO2, and transparent gels were formed in the rest compositions. Morphology of these particles was obtained by SEM. It was found the opaque gels consisted of spherical particles and the transparent gels consisted of bulk matrix. The opaque gels containing spherical particles were of different degree of agglomeration depending on the compositions. The compositional homogeneity of the particles were confirmed by EDX. It was found that sub micron spherule particles formed during gelation process were aggregated or packed together form micro-sized spherical particles. Gels were heat treated at 200, 400 and 600 deg for 1 hour to study the crystallization behavior. Key Words:SiO2-TiO2-ZrO2 gel, Gelation time, Gel Particle, Formation of spherical particle, Crystallization
A STUDY ON SNOW STICKING WEIGHT TO WATER-REPELENT COATINGS
Hiroyuki SAITO, Ken-ichi TAKAI, Hisayoshi TAKAZAWA and Goro YAMAGUCHI
Abstract:When snow or ice sticks to radio communications antenna, it sometimes causes signal transmission problems. In many cases, the degree to which snow or ice sticks to antennas is based on the degree of adhesion. We have been developing water-repellent coatings to prevent such adhesive problems. In this paper, the snow adhesive property of these water-repellent coatings is experimentally studied. We obtained following results. (l) Much more fallen snow adheres to FRP samples than water-repellent coatings. (2) Much more fallen snow adheres to samples at {l.5 deg than at -5deg. (3) Snow naturally falls off of the surface when its weight reaches a certain value. (4) The estimated value of snow falling off consists with experimental value. Key Words:PTFE, Coating, Repellent, Snow, Antenna, Communication
HEAT TREATMENT EFFECT ON TRANSFORMATION PROPERTIES OF TiNi SHAPE MEMORY ALLOY FILM
Sotohiro TAKABAYASHI, Katsumi TANINO and Kazuo KITAGAWA
Abstract:The heat treatment effect on transformation properties of a NiTi shape Memory Alloy(SMA) film is discussed. TiNi SMA films were deposited by using sputter deposition technique, and were then solution-treated and aging-treated. The phase transformation properties were investigated by means of a differential scanning calorimeter (DSC), X-ray diffractometer and a transmission electron microscope (TEM). As sputtered film had an amorphous structure with fluctuating density of titanium atoms. The films solution-treated at 600 deg and aging-treated at 400deghad several kinds of phases. The rhombohedral phases, austenite phases and amorphous phases could be distinguished within the same film. The film solution-treated at 800 deg and aging-treated at 400deg showed the largest enthalpy of the transformation and had the preferable crystalline structure. The samples solution-treated at 1000 deg, in which NiTi were resolved partially into Ti2Ni and Ni4Ti3 were more brittle. Key Words:Shape memory alloy, TiNi film, Heat treatment, RF magnetron sputtering
MOLECULAR DYNAMICS SIMULATION OF THE INFLUENCE OF CRYSTAL IMPERFECTION ON NANO-MACHINING MECHANISM
Katsuhiro MAEKAWA
Abstract:Establishment of nano-scale machining technologies is required in the field of ultra-precision fabrication where it is important to clarify cutting phenomena such as chip formation, cutting force, surface roughness and subsurface damage. The present paper investigates the diamond machining of a copper single crystal with atomistic defects by means of molecular dynamics simulation. Postulating the Morse potential, the influence of initial vacancies and duplex cutting on the cutting mechanism is analysed when a (lll) plane of the crystal is orthogonally machined in a [101] direction. Existing vacancies and edge dislocations in the copper result in further disorder of the lattice structure and an increase of cutting force owing to the interaction between the defects and the dislocations propagated from the tool tip. These phenomena can be observed at a vacancy density of 0.5 %. In the case of the duplex cutting of the perfect crystal, displacement of the work atoms is limited to at or just below the finished surface, requiring a lower cutting force and producing more work atoms removed as a chip. These results suggest that a prerequisite for a damage-free machined surface is that the work material be as pure and perfect as possible. Key Words:Molecular dynamics simulation, Nano-scale machining, Crystal imperfection, Cutting mechanism, Sub-surface damage
FET-BASED HOMOGENIZATION ALGORIYHM USING DIGITAI IMAGES
Kenjiro TERADA, Katsuyuki SUZUKI and Hideomi OHTSUBO
Abstract:The applicability of the FFT-based algorithm for evaluating the mechanical behaviors of composites is investigated from practical viewpoints. After the iterative numerical algorithm is presented, the computational efficiency is compared with that for conventional FEM-based homogenization algorithm and then extended to nonlinear analyses such as elastoplastic problems. In addition to preferable features in micro structural analyses, there are several advantages over the conventional approach by the FEM-based homogenization method. While the method is for evaluating the micromechanical response to the macroscopic deformation, the solution method can also be utilized to estimate the homogenized material constants. In the numerical examples, the digital image processing technique is extensively utilized to define the geometry of microstructures so that the method would not suffer from modeling effort. Key Words:Composite materials, FFT-base solution method, Homogenization method, Digital images
CREEP LIFE ASSESSMENT OF 2.25Cr|1Mo PIPING STEEL AND OF ITS SIMVLATED HAZ MATERIAL
Kazunari FUJIYAMA, Takashi ISEKI, Atsushi KOMATSU and Nagatoshi OKABE
Abstract:A creep life assessment method was proposed for base metal and HAZ or 2.2Cr-1Mo steel STPA24 used in high temperature steam piping of fossil power plants. Microstructural observations and hardness measurements were carried out for base metal and simulated HAZ material aging and creep testing. Simulated HAZ material showed significant softening during thermal and creep exposure, but base metal showed less softening. Hardness equation was established based on the kinetics of carbide coarsening and recovery of dislocation substructure. Creep damage was evaluated by damage mechanics in combination with softening equation and creep constitutive equation. The proposed method can be applied to assess creep life of Cr-Mo steel HAZ in actual components. Key Words:Life assessment, Creep, Degradation, Damage, Hardness, 2.25Cr-1Mo steel, Ostward ripening
CORROSION/DEFORMATION INTERACTIONS IN URANIUM/WATER SYSTEMS
Arie BUSSIBA, Henry ALUSH and Yosef KATZ
Abstract:Aqueous corrosion/Deformation Interactions (ACDI) in uranium and uranium alloys actually exhibit complicated mechanical damage processes. In this context, the exploration of the dominant micromechanical mechanisms vis-a vis experimental confirmations remain an unsettled issue. Various mechanisms might be involved in such environmental effects, starting from stress corrosion cracking (SCC) hydrogen embrittlement, up to brittle film fracture or film-induced cleavage, enhanced or inhibited by diffusion barriers. These on top or hybrid formation which potentially affects the local mechanical/chemical driving field. Thus, beside the driving force modifications, the reduction of the fracture resistance requires appropriate evaluations. The main objective in the current phenomenological investigation was, to provide additional findings as related to damage evolution in specific ACDI systems. In fact, the present selected systems allowed further insights into a low symmetry, orthorhombic crystal structure case. Experimentally, sustained load, slow strain rate (SSR), monotonic and fatigue tests in fracture mechanics framework were performed, supplemented by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) observations. In addition, X-ray, Fourier Transform Infrared spectroscopy (FTIR) techniques and acoustic emission (AE) tracking were utilized. Experimental findings are analyzed and discussed with emphasis to fractographic observations and kinetics associated with the crack propagation stage. These beside development in modeling aspects founded on a stepwise decohesion processes. Key Words:Corrosion-deformation interaction, Uranium-water, Slow strain rate test, Stress corrosion cracking, Fatigue crack propagation, Hydrogen embrittlement, Decohesion
PHYSICAL PROPERTIES VARIATION OF CORROSIVE REINFORCEMENT DUE TO S0DIUM CHLORIDE ATACK
Yoshinobu KOIBUCHI and Kiyoshi KATO
Abstract:This paper deals with the experimental investigation on the effects of the corrosion of reinforcement due to the sodium chloride on the yield strength, the tensile strength and the elongation relating to the fundamental concept of the RC structure design. The main conclusions are as follows: (l) The long term corrosion rate over four cycles becomes a constant value of about 180 mdd. (2) The corrosion degree of round bar is much larger than that of steel plate. Therefore, the covering of the RC members is very important. (3) The tensile strength of reinforcement depends on the "structure-sensitive" property concerning the pittings. (4) The special attention must be paid to the tensile strength, the elongation and toughness of the reinforcement from the viewpoint of the earthquake-resistant RC structure. Key Words:Reinforcement, Corrosion, Sodium chloride, Durability, RC structure, Yield strength, Tensile strength, Elongation