Research Reports 2001　Up date　2003.7.16
 
Abstracts of Papers     
  1. Evaluation of High Viscosity of Solidified Lubricants at High Pressure by Rayleigh Light Scattering and Photon Correlation Technique, Yuichi NAKAMURA, Masayuki TSUNODA*, Tatsuya MATSUI* and Ikuya FUJISHIRO*: JSME International Journal, Series C, Vol. 44, No. 1, pp. 237-243, 2001.

    A new viscosity measuring system was designed and set up employing Rayleigh light scattering and the photon correlation technique in which a high-pressure diamond-anvil cell (DAC) was used. Two kinds of experiments were conducted. One was the measurement of a dilute suspension of polystyrene latex spheres in liquid lubricant and W/O emulsion. Correlation functions induced by the Brownian motion of fine spheres in the lubricant were observed and the viscosities were obtained, the measurement time of which was one-tenth shorter than that of the falling-body method. The other experiment was the measurement of 5P4E (polyphenyl ether) and DOP (dioctylphthalate) without mixing polystyrene spheres. Very weak but observable correlation functions related to structural relaxation were observed and the viscosities of solidified lubricants (about 10<SUP>9</SUP> Pa･s), obtained in a very short time by introducing a shift factor for relaxation time, were consistent with those extrapolated from data obtained using the falling-body method.

  2. Improvement of Pure Stretchability by Overlapping Sheet Metals [in Japanese], Masanori KOBAYASHI*, Nobukazu HAYASHI* and Yasushi KUROSAKI: Journal of the JSTP, Vol. 42, No. 483, pp. 328-332, 2001.

    This study showed the increase in critical forming depth in a pure-stretching test using overlapping sheet metals. In this study, two soft metal sheets were investigated. Two sheets were overlapped with each other without lubricant. The critical height of the two overlapping sheets was larger than that of the original single sheet. Radial distribution of thickness strain after stretching was measured and it was observed that the two overlapping sheets had the same large fracture strain. To confirm these results, the contact plane between the overlapping sheets was lubricated. In spite of the overlapping using the same sheet, the necking position of the inner sheet was located near the punch top compared with that of the outer sheet. Thus, it was confirmed that the discrepancy of the necking position brought about the improvement in pure stretchability.

  3. Material Processing Using Microorganisms (An Investigation of Microbial Action on Metals) [in Japanese], Yasushi KUROSAKI, Masahito MATSUI, Yuichi NAKAMURA, Kenichi MURAI and Toshio KIMURA: Trans. JSME, Series C, Vol. 67, No. 661, pp. 3013-3020, 2001.

    Seeds of developing a new type of material processing using a microbiogenic function are searched with a microbial corrosion test of metals under the seawater. The behavior of microorganisms on corrosion of metals (mild steel, copper and aluminum sheets) is examined, and their action on these metals is discussed. As a result, three processing methods (biomachining, biodeposition and biorecycling) are proposed and discussed.

  4. Engineering in Fabrication of a-c Oriented YBCO Thin Films, Tamio ENDO, Ken-ichi ITOH, Akinori HASHIZUME, Hideaki KOHMOTO, V. V. SRINIVASU, Masahito MATSUI and Yasushi KUROSAKI: Proceedings of 6th Advanced Studies on Superconducting Engineering, pp. 47-52, 2001.

    Control of a-c orientations in YBCO thin film growth on MgO by ion beam sputtering was thoroughly investigated with varying essential deposition parameters. All the results indicate that the surface migration of deposited particles determines the a-c orientations. The film deposited on rough-surface substrate can verify this mechanism.

  5. Sound Velocity Dispersion for Lubricant Oils in Brillouin Light Scattering and Mechanical Properties at High Pressure Up to 5 GPa, Yuichi NAKAMURA, Takahiro KIYONAGA*, Ikuya FUJISHIRO* and Yasushi KUROSAKI: Proceedings of International Tribology Conference, Nagasaki, II, pp. 1215-1220, 2001.

    Using Brillouin light scattering technique, frequency dispersions of sound velocity (about 7 % increase) for some lubricant oils were obtained at atmospheric pressure with varying frequency ( from about 5 GHz to 10 GHz). The dispersions seemed to be induced by the viscosity and viscoelastic effect. The dispersion disappeared at high pressure immediately in a diamond-anvil high-pressure cell (DAC) device and the disappearance maintained up to 5 GPa in loading process. In unloading process, unpredictable large difference of sound velocity in orthogonal directions was observed that seemed to be caused by the unisotropy of elastic modulus due to uniaxial compression feature of DAC. Hysteresis between loading and unloading may bring some influence on solidified oil film under Hertzian pressure profile. Dispersion of elastic modulus at high pressure was also evaluated based on reference data.
  6. Research on Biomachining Using Marine Microorganisms, Yasushi KUROSAKI, Masahito MATSUI, Yuichi NAKAMURA, Hisashi KATOH* and Junji YOKOTA*: Proceedings of IMMM2001, pp. 289-294, 2001.

    As an attempt to develop a new type of machining process, biomachining utilizing the microbiologically influenced corrosion (MIC) on metals is experimentally examined. Based on an observation of the corrosion behavior by marine bacteria, biomachining is tested for mild steel sheets in the seawater and small circular holes with 1 or 3 mm in diameter are successfully produced on the specimen surface. Various influencing factors on machinability, i.e., bacteria, hole diameter, test time, temperature, light irradiation, aeration, magnetic field and additives, are examined, and a method for improving the machining rate is proposed. Especially, biomachining combined with a magnetic field (BMM) is found to be effective to improve not only the machining rate but also the surface roughness of produced holes. Finally, this method is applied to produce such very fine holes as required in making micromachines.
  7. Eccentricity and Asymmetric Metal Flow in Plane Strain Extrusion, Masahito MATSUI, Yasushi KUROSAKI, Yubo SONG* and Hatsuhito NISHIJIMA*: Proceedings of IMMM2001, pp. 351-356, 2001.

    Asymmetric metal flow caused by eccentricity in plane strain backward extrusion is examined. The moment exerted on the punch head and the eccentricity between the punch and die are measured throughout the process. The resultant frictional force on the punch face and deviation of punch load center from the punch center are estimated from the moment and the eccentricity. These results are compared with FEM simulation. When the initial eccentricity is small, the eccentricity induced by certain disturbances increases with punch penetration. Conversely, when the initial eccentricity is large, the eccentricity decreases with punch penetration.
  8. Micro/Nanoscopic Observation and Fractal of Adhesion Particles in Metal Forming, Yasushi KUROSAKI, Masahito MATSUI, Ken YAMAZAKI* and Tadashi YAMAZAKI*: Proceedings of IMMM2001, pp. 413-420, 2001.

    In order to obtain fundamental information about the adhesion phenomenon in metal forming, a simple compression test of aluminum strips is carried out, and adhesion particles produced on the tool surface are examined in the micro/nanometer range from a viewpoint of the fractal geometry. The adhesion particles are found to be fractal, indicating that their shapes are self-similar, but their size distribution related to a grain growth is nonfractal. An atomic force microscope (AFM) is a useful tool to estimate fractal dimensions of the adhesion particle surface as well as those of tool and specimen surfaces. Various fractal dimensions obtained for the particles and the tool and specimen surfaces are compared to each other and discussed. Geometrical conditions of the tool and specimen surfaces necessary for preventing adhesion are pointed out. Finally, a method for computer simulation of an adhesion feature is presented, and its validity is confirmed.

  9. Elastic Modulus of Lubricants at High Pressure by Brillouin Light Scattering, Yuichi NAKAMURA and Ikuya FUJISHIRO*: Proceedings of IMMM2001, pp. 421-428, 2001.

    Elastic modulus of the order of GHz frequency were evaluated from the sound velocity of Brillouin scattering light under high pressure with a diamond-anvil high-pressure cell. Such a dynamic elastic modulus for polyphenylether from the sound velocity on transverse mode and on longitudinal mode was larger than static one and the difference decreased with raising pressure up to 4GPa. Application of a viscoelastic model for these features was attempted with a volume viscosity. The ratios of elastic moduli were compared with those of solid materials.
  10. Compression Characteristics of DAC with Lubricants Estimated Using A Laser Displacement Sensor, Yuichi NAKAMURA, Roppei ITO* and Yasushi KUROSAKI: Proceedings of IMMM2001, pp. 429-436, 2001.

    Compression characteristics such as oil leakage of a diamond-anvil high-pressure cell (DAC) with lubricant were estimated using a high resolution laser confocal displacement sensor. Pressure-volume relations of a traction oil and methanol were measured and discussed comparing with existing data and oil leakage was resulted to be very small and appropriate evaluation of high pressure volume of lubricants was proved to be possible in spite of rough estimation of the shape of the plastically deformed pressure chamber.
Abstracts of Books and Reviews
  1. Deposition and Recycling of Metals by Bacteria [in Japanese], Yasushi KUROSAKI, Masahito MATSUI and Yuichi NAKAMURA: Journal of High Temperature Society, Vol. 27, No. 1, pp. 23-27, 2001.

    As a new type of metal processing using bacteria, biodeposition and biorecycling advanced by the authors are introduced. In the beginning, general microbiological actions to metals are reviewed. Next, based on our finding that a kind of anaerobic bacteria can precipitate metal grains on a substrate, biodeposition referred to as MBD are presented, and are shown to be successful in producing fine copper grains on the copper substrate processed in the seawater. Thirdly, a concept of biorecycling is introduced. It is based on the fact that a certain kind of microaerobes can transform iron red rust into ultrafine-grained magnetite. It is shown to be useful to accomplish value-added recycling to produce magnetite from steel scraps or red rust at a low cost.

  2. Basic Experiments and Application of Traction Drive Variator [in Japanese], Yuichi NAKAMURA, Yasushi KUROSAKI, Masahito MATSUI and Kenichi MURAI: Research Information of Mie 2001, pp. 25, 2001.

    Traction drive, the variator for power transmitting by rolling friction with a few hundreds nanometer oil thin film, is superior to gear trains for low noise, low vibration, high speed and high accuracy. It enables to construct continuously variable transmission (CVT) that gear trains cannot, and it was assembled in passenger cars recently. The roller contact area transmitting power is suffer from high pressure over a few GPa and power transmitting behavior with oils is not investigated enough. Establishment of the traction drive tester and application of traction drive are introduced.

  3. High-Pressure Viscosity and Traction Characteristics [in Japanese], Yuichi NAKAMURA: J. Japan Soc. of Tribologist, Vol. 46, No. 5, pp. 368-373, 2001.

    High-pressure viscosity is the fundamental property for the tribological evaluation (i.e. friction and wear) of rolling bearings, gears and traction drives such as continuously variable transmission (CVT). The mechanical behavior of lubricants under high pressure is classified into the viscous region, the viscoelastic region and the elastoplastic region (non-Newtonian region) in terms of density (bulk modulus) measurements. Even in the non-Newtonian region, high-pressure Newtonian viscosity is still fundamental and indispensable for the above classification. Viscosity changes drastically with pressure (an approximate exponential function of pressure) and the pressure-viscosity coefficient is important for EHL and traction analysis. This paper introduces the application of a diamond-anvil pressure cell (DAC) for tribological measurements. A falling sphere viscometry in the DAC facilitated the viscosity measurements up to 2 GPa. The relation between high-pressure viscosity and traction characteristics is also described.

  4. Lubricant's Properties under High Pressure and Tribology [in Japanese], Yuichi NAKAMURA: The Review of High Pressure Science and Technology, Vol. 11, No. 2, pp. 145-152, 2001.

    Physical properties of lubricants under high pressure (e.g., density, elastic constant and viscosity) are the fundamental properties for the tribological evaluation (i.e. friction and wear) of rolling bearings, gears and traction drives. This paper introduces the importance of such physical properties of lubricants under high pressure in tribology and the application of a diamond-anvil pressure cell (DAC) for tribological measurements. A falling sphere viscometry in the DAC facilitated the viscosity measurements up to 2 GPa. A photon-correlation technique with laser light scattering in the DAC enabled the viscosity estimation of solidified glassy state lubricants (viscosity is about 109 Pa･s) from structural relaxation. Dynamic elastic moduli were obtained from Brillouin light scattering measurements in the DAC up to 4 GPa, which enabled the evaluation of the frequency dispersion of elastic moduli with quasi-static data.
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