Plastic deformation energy is transformed into heat in about 90 percent. If heat generation with plastic deformation is available for plastic deformation, deformation resistance can be reduced. We propose a new cold stamping technology characterized by using a die which has low thermal conductivity to apply heat generation with plastic deformation to uniform temperature rising of processed material. Our aim in this study is to achieve ecological and technical advantages such as energy saving, high formability and high dimensional accuracy. In this report, the effect of die materials and deformation rate on deformation load was examined by compression tests on SUS304, TW340 and A5052. The following results were obtained: 1) Deformation load on SUS304 and TW340 using ZrO_2 for the die is lower than using SKD11 for the die to make efficient use of heat generation with plastic deformation. 2) Deformation rate has optimum value related to thermometric conductivity of processed material.

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A biggest issue of some problems preventing the widespread use of Magnesium alloy is how to control its poor formability. Generally, improvement in formability was made by process with high process temperature. Here, the concept of temperature descent is provided and the usefulness of cooling down the process temperature is shown by the comparison to process with constant temperature. The object of this paper is to analyze the effect of temperature descent on improvement of stable formability and to demonstrate actually the utility. This paper contains both experimental results and theoretical analysis of the onset of diffuse necking. Actually at elevated temperature in tensile test by using Magnesium alloy hollow tube, where flowing cool air inside pipe may effectively lower the temperature of the work during the test, a significant rise in stable deformation range could be observed. The result may be applied to any other metal, being independent of metal class in the analysis, thus generalized concept seems to be reached to extension in stable deformation range of metals with poor formability.

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Dry forming, which means press forming without lubricants, is an attractive forming technique for the zero emission of lubricants. As one of the dry press forming techniques, the application of dies coated with a CVD diamond film in forming tools has been proposed for their high tribological properties, abrasion resistance and heat resistance. On the other hand, in the spinning process which is the flexible process, the lubricant between the tool and the workpiece is required in order to smooth surface of product. So, the diamond coated tool is utilized in nosing process without lubricants in order to improve the surface roughness of the workpiece in this study. The effect of the diamond coating on the surface texture was confirmed. The surface roughness of the workpiece with the diamond coated tool was in the same range of roughness with the lubricant.

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The major problem for forging of magnesium alloy is the lack of process ductility at the low temperature. The Mg_<96>Zn_2Y_2 is a high strength magnesium alloy material developed by Mr. Kawamura in Japan. Mg_<96>Zn_2Y_2, a newly developed high strength magnesium alloy material is expected as forged parts of the automobile and materials for aerospace applications. It is necessary to clarify forging process characteristics of this material. The purpose of the present study examined increasing of ductility of forging process for the Mg_<96>Zn_2Y_2 material. For this purpose, cylinder upsetting tests of were performed by this method of two stages. In addition, the deformation resistance and ductility of the material were examined. The two stages forging process is effective for an increase of ductility of the material.

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In plastic forming, deformation resistance of a material is generically decreased by superimposed ultrasonic vibrations as "Blaha effect". The mechanism of these effects is not cleared entirely. Moreover, there are not many studies for the superimposed ultrasonic vibration technique on tensile and compressive test using several alloys. It is necessary to clear the mechanism of the stress decreasing owing to ultrasonic vibration technology. Therefore, in this study, the stress-strain curves of (AZ31) magnesium alloy were obtained superimposed ultrasonic vibrations on tensile and compression tests. As a result, the effect of superimposed ultrasonic vibrations on compression test was confirmed. the compression stress decreased pronouncedly. On the other hand, superimposed ultrasonic vibrations on tensile test is not so much stress decreasing as compared with compression test.

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To prevent galling of billet in forming of hole with high aspect ratio, the forming method with a punch with internal channel for lubricant is proposed using a servo press. In the proposal method, the punch moves in a manner combining pulsed and stepwise modes by controlling the press ram of servo press. Liquid lubricant in the internal channel of the punch is induced to the bottom part of the formed hole during retreating of punch became atmospheric pressure in the hole is reduced. The appropriate forward stroke of the punch for preventing the galling is determined from the amount of the lubricant and the observation of the hole surface.

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The mechanical properties of the clustered shrinkage pores in high-pressure die cast aluminum alloy ADC 12 were evaluated through the serial sectioning experiment and the image-based finite element analyses. We have investigated the effect of pores on the fatigue strength, and found a mechanical significance of the clustered shrinkage pores, which considerably undermines the strength of die cast aluminum alloys. In this study, we constructed twenty three unit cell models for the homogenization analysis based on the three-dimensional image of a clustered shrinkage pore. From the homogenization analysis and uniaxial extension analysis, we obtained the equivalent elastic constants and the micro stress concentration factor as a function with respect to the porosity volume fraction.

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Long cups of magnesium alloy were formed at ambient temperatures by multi-stage deep drawing processes. In general, typical uses of magnesium alloys are for automobile and aircraft components, portable device, luggage, and care goods. However, magnesium alloys are difficult to plastically deform at room temperature. This is due to the hexagonal close-packed structure restricts slip to the basal planes. On the other hand, Mg-Li alloys, which have the BCC crystal structure, can be formed at room temperature. In multi-stage deep drawing, the Mg-Li alloy sheets were employed and a flat sheet blank is formed into a cylindrical by a punch. Various cups were drawn by exchanging the punch and ringed die. The die was flat in the first stage, and was taper without a blankholder in the subsequent stages. The effects of the ratio of blank diameter to punch diameter and blank thickness on the deep drawability were examined. It was confirmed that the Mg-Li alloy long-cups were successfully formed by a multi-stage deep drawing operation in cold.

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The effect of shot peening (SP) at various temperature on mechanical properties, i.e. fatigue, tensile and bending characteristics, for fine-grained AZ31 magnesium alloy was investigated. The residual stress was occurred by SP, which was examined at worm temperature was higher than those of room temperature SP. Although elongation decreased little for this material with high residual stress, tensile and bending characteristics improved remarkable. Especially, the endurance limit of fatigue improved 22% higher on comparison with that of non-SP material. On the other hand, under high temperature SP, the material which have the graded microstructure from surface to about 0.5mm in insides was able to be created.

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This study examined the relationships of mechanical properties and plastic work parameters, characteristics of super-plastic deformation, and structural changes for fine-grain structure AZ31 Mg alloy by severe strain forming at strain rate from 10-4 to 10-2s-1 under high temperature (423-623K). It was found that at test temperature 623K and strain rate 10-4, strain rate sensitivity exponent, m-value remained at about 0.3 over and an elongation was examined 200% or over at all sampling direction, that is, the superplastic deformation behavior occurred at these conditions. This fined structure material has remarkable high deformability on comparison with those of commercial material.

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Mg-Zn-Y alloys were prepared by high frequency induction melting in an Ar atmosphere. The influence of extrusion condition on microstructure and mechanical properties of Mg_<96>Zn_2Y_2 (at. %) alloys by hot extrusion was investigated. Extruded specimens composed by recrystallization region and worked region and LPSO phase. Extrusion ram speed at 2.5 mm/s, yield stress and tensile strength showed the 395 MPa and 432 MPa at room temperature and 281 MPa and 311 MPa at 523 K, respectively. On the other hands, yield stress and tensile strength slightly decrease with increase of the recrystallization region due to the achieved temperature after the processing became higher than the recrystallization temperature of α-Mg phase after the extrusion. However, the strength did not show a remarkable decreased, and formability could be improved because the elongation improved. It was able to maintain high strength so that an LPSO phase restrained grain growth. It is important that the LPSO phase was fine dispersed in a α-Mg phase in the Mg_<96>Zn_2Y_2 alloys to maintain strength and elongation.

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In the present study, fatigue tests were carried out to understand the influence of mechanical surface treatment on fatigue behavior of extruded AZ61 magnesium alloy at a stress ratio of -1 and frequency of 20 Hz under ambient environment. The mechanical surface treatments used in the present study were: (a) Shot-peening, (b) Micro-peening and (c) Barrel processing. From the results it was found that fatigue strength of shot-peened specimen degraded by about 30% compared to the bulk specimen. Cracks were nucleated from dents on the surface induced by shot-peening, which then propagated until final failure. On the contrary, both micro-peened and barrel processed specimens showed the same level of improvement in fatigue strength, which was about 15% higher than the bulk specimen. Though cracks were nucleated from the specimen surface with relatively small defects, the compressive residual stress induced near surface retarded the crack propagation, which was dominant for the improved fatigue strength.

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The tensile properties of carbon nanotubes (CNTs) grown on high tensile strength polyacrylonitrile (PAN)-based (T1000GB) carbon fibers have been investigated. The Fe(C_5H5_)_2 (ferrocene) catalyst was applied to the T1000GB fiber bundles using thermal chemical vapor deposition (CVD) in vacuum. The CNTs were also grown on the carbon fiber surface using thermal CVD. The CNTs grown on carbon fibers were examined using a high resolution scanning electron microscope. Tensile tests of single carbon fibers were performed using a universal testing machine at gauge length of 5 and 25 mm. The statistical scattering of the tensile strength was also evaluated. The results clearly show that grafting of CNTs improves the mechanical properties and the Weibull modulus of high tensile strength PAN-based carbon fibers.

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Thin film shape memory materials including shape memory alloys (SMAs) are promising smart materials for MEMS actuators because of its large recovery stress and strain. For development of novel SMAs, combinatorial approach is focused on. However, the approach requires high-throughput characterization method of thin film SMAs. In this paper, we proposed novel measurement method of phase transformation temperatures of SMAs for combinatorial approach, which means applicable method to integrated thin film samples. The method use thermography and detect two-way transformation as emissivity change. The proposed method is demonstrated on Ti-Pd-Ni SMA sample which is heated and then cooled in vacuum furnace, and as results, clear changes of emissivity can be detected in both cases. The results are then compared with electrical resistivity change and results of differential scanning calorimetry (DSC). It is then turned out that the detected temperatures of emissivity change correspond with the conventional transformation temperatures. The result of this paper is precursor to achieve the high-throughput characterization of transformation temperatures of thin film SMAs.

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In recent years, many composite materials, such as CFRP, are increasingly used for the structure of an airplane. A composite material with many features may also cause exfoliation and a fracture by a shock. Therefore, it is desirable to perform health monitoring of a structure periodically. However, since deburring and exfoliation are caused when machining a composite material, it may be damaged when attaching a sensor and an actuator. In this research, it succeeded in adding a sensor and an actuator function to a composite material, without processing it by embedding fiber type piezo-electricity material at the time of fabrication of a CFRP composite material.

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This paper presents the characterization of output power of the metal-core piezoelectric ceramic (PZT) fiber/aluminum composite. As the piezofiber is very fragile, the interphase forming/bonding (IF/B) method proposed by Asanuma was used for embedding it in an aluminum matrix without fracturing it. In this study, output power characterization of the piezo-composite specimen was done by an oscillation test, and it was found that 1) the output power generated by the specimen increases with increasing the square of its strain, and 2) the output power increases in proportion to its oscillation frequency.

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In this paper, bucky-gel electrodes containing various ionic liquid species were prepared by casting, using 'bucky gel', a gelatinous room-temperature ionic liquid (IL) containing single-walled carbon nanotubes (SWCNT). Their electrochemical impedance responses were measured and analyzed. Also, the electromechanical responses of the actuators composed of two bucky-gel electrodes sandwiching an ionic-liquid gel layer were studied by measuring the displacement due to an applied sinusoidal voltage at various frequencies. Based on the experimental results, the electromechanical responses of the bucky-gel actuator were analyzed by taking into account the electrochemical properties of the bucky-gel electrode. Accordingly, an electromechanical model for a bucky-gel actuator was obtained.

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This paper describes a novel configuration of electrodes used to actuate ionic polymer-metal composites (IPMCs). IPMCs are smart materials usually actuated by a pair of electrodes fixed against them. In this study, the anode is fixed to the actuator while the cathode only touches it. It was verified that the IPMC can bend enough to lose connection. This configuration obtains oscillation from a DC input, characterized by quick separations and slow returns. Actuation based on transient contact between IPMCs and electrodes has the potential of simplifying current mechanisms.

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In order to develop the new function of the shape memory materials, the shape memory composite (SMC) with the shape memory alloy (SMA) and the shape memory polymer (SMP) was fabricated, and the three-way bending motion and recovery force were investigated. The results obtained can be summarized as follows. (1) Two kinds of SMA tapes which show the shape memory effect (SME) and superelasticity (SE) were heat-treated to memorize the round shape. The shape-memorized round SMA tapes were arranged facing in the opposite directions and were sandwiched between the SMP sheets. The SMC belt can be fabricated by using the appropriate factors: the number of SMP sheets, the pressing force, the heating temperature and the holding time. (2) The three-way bending movement in the fabricated SMC belt is observed based on the SME and SE of the SMA tapes and the glass transition of the SMP sheet during heating and cooling. (3) If the SMC belt is heated and cooled by keeping the bent form, the recovery force increases during heating and decreases during cooling based on the three-way properties of the SMC. (4) The development and application of high-functional SMCs are expected by the combination of the SMA and the SMP with various kinds of phase transformation temperatures, volume fractions, configurations and heating-cooling rates.

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In order to develop a brain spatula or a brain retractor made of a shape memory alloy (SMA), the bending fatigue characteristics of the brain spatula of TiNi SMA made by the precision casting were discussed. The results obtained can be summarized as follows. (1) At the room temperature, the fatigue life in pulsating-plane bending is longer than that in alternating-plane bending. (2) The relationship between the dissipated work and the number of cycles to failure can be expressed by the unified power function for alternating- and pulsating-plane bendings. (3) The above mentioned characteristics of the SMA-brain spatula obtained in this study can be substantially applied to the development not only for the brain spatula but also for other retractors and instruments used in other surgery operations.

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This study aims to develop the MIM process for manufacturing the micro heat sinks made of copper / diamond composites with high thermal conductivity. Diamond particles were added into the feedstock composed of copper powder and polyathetal-based binder. The compound feedstock was molded into sacrificial plastic mold (SP-mold), and the green compacts with micro-pillars were obtained and removed the SP-mold by solvent extraction. Nano-sized copper powder was used for drastically decreasing the sintering temperature to prevent from occurring thermal damages on the surfaces of diamond particles. The sintered parts were also prepared by spark plasma sintering in contrast with furnace sintering, and they were evaluated by density and thermal conductivity measurements. The experimental results showed that using nanopowder could obtain a sufficient high sintered density under low sintering temperature.

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The polyurethane composites dispersed with powders mixture of LaNi_5 hydrogen storage alloy (35vol% of LaNi_5) and Pd-Al_2O_3 catalyst powders were prepared by solution cast method. The unimorph sheet constructed with the driving polyurethane composite and supporting thin sheet with high specific stiffness was prepared to generate the bending strain of reversible up motions at horizontal direction,. The operation temperature dependent motion strain has been studied.

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This paper describes the effect of humidity on the shape of the active laminate. It was made by hot-pressing of an aluminum plate as a high CTE material, a unidirectional CFRP prepreg as a low CTE material and an electric resistance heater, a unidirectional GFRP prepreg as an insulator between them and copper foils as electrodes. In this study, it was clarified that the curvature of the active laminate is increased by moisture absorption, and the saturated value is dependent on the environmental humidity. In addition, the curvature change is found to be repeatable in the experimental range. The curvature change decreases with increasing the temperature of specimen.

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The multi-scale pattern composed of different scale patterns has been developed to measure the localized deformation for structure materials with complex microstructure. The measurement ofmultiscale deformation and strain distribution was investigated by in-situ FE-SEM observation. The measurement method was applied to investigate local deformation o f the hierarchical structure material. In-situ observation of the material subjected to tension was conducted to identify local deformation under various applied loading. Heterogeneous intrinsic grain-scale plastic defrmation was clearly observed and it increased with increasing macro-scale plastic deformation.

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In the field of material science and engineering, it is often required to measure internal temperature of a material being heated at high temperatures. In particular, in sintering or moulding processes for ceramics as well as metals, not only temperature but also its distribution inside the material is strongly required to be measured because such temperature distribution plays an important role in the processes at high temperature. In this work, an effective ultrasonic technique with transverse wave has been applied to alumina and steel for monitoring the one-dimensional temperature distribution during heating. It is expected that the use of transverse wave provides improvement of the accuracy in determining temperature because of its relatively slower velocity. The temperature distributions and their transient variations determined by the ultrasonic method almost agree with those obtained using thermocouples or an infrared radiation camera. Thus, it is demonstrated that the ultrasonic method with transverse wave is useful for temperature monitoring even for sintered material such as alumina.

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The sinking electrical discharge machining with the ultrasonic vibration apparatus was examined on the cemented carbide material using a conventional EDM system. The ultrasonic vibration apparatus was modified the unit to be available in the longitudinal and the transverse motion independently. The effect of vibration direction was evaluated from the point of view of the removal rate, the surface roughness and the wear ratio. As the results, the removal rate and the surface roughness were improved with operating the combined longitudinal and the transverse motion.

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This study aims to evaluate position and size of corrosion on a steel plate using low-frequency So mode Lamb waves. Some dome-shaped artificial defects with diameter of 4 mm to 30 mm and depth of 2.7 mm to 5.1 mm on 6-mm-thick carbon steel plate were machined. Low-frequency So mode lamb wave whose amplitude profile along thickness of a plate has a uniform was generated by striking a distal plane of a plate with a rectangular type longitudinal PZT transmitter. We can detect the defect with 4 mm diameter and 2.7 mm depth and also detect aligned defects with separation distance of 100 mm individually. Distance to the defects from the transmitter could be estimated from arrival times of reflected wave by the defects and calculated velocity of So mode lamb wave. Wave amplitude reflected by the defects that was normalized by amplitude of wave reflected by an opposite edge to incident point was almost proportional to cross-sectional area of the defects

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