The adhesion strength and dismantlability of adhesion joints using novel technique of dismantlable adhesive. The adhesive, which include water absorbing polymer and can be expanded in water is capable to be separated by absorbing water after the service life. The most typical mode of fracture is interfacial fracture between the surface of adherends and the adhesive due to the force caused by the expansion of the adhesive. In this paper, The relation between soaking time of the joints in water and COD or energy release rate was investigated experimentally.

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In recent years, from viewpoints, such as energy saving and economical efficiency, in order to make a product light, the products which use aluminum for part material are increasing in number, and it is thought that this tendency also continues from now on. However, it has the fault that hardness of aluminum is low and the surface tends to get damaged compared with iron base material. Then, in this research, production of surface modificated layer was tried on the aluminum alloy (A5083) surface part by irradiating YAG laser beam, after sticking stainless steel powder to the surface. Consequently, thick surface modificated layer was able to be obtained by the high hardness which a crack does not occur.

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The present paper refers to experimental studies on alumina, silicon nitride and pottery sintering process using the 28GHz mm-wave energy generated by a Gyrotron is described. The results may be summarized as follows: (1) Work material are densified in low temperature and short time by sintering of microwave heating compared with conventional heating; (2) The sintered bodies exhibited high density and fine crystalline structure. (3) Control of heating is suitable for the mechanism of mocrowave sintering. The cause or mechanism of these phenomena has yet to be sufficiently clarified. It largely depends upon future multilateral studies.

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Experimental apparatus used in this study was a conical metal block above which has a metal disk as a flyer plate. When the metal disk is accelerated by explosive settled above the disk, the disk collides to surface of the conical metal block. Since the disk collides with inclined angle, metal jets launched with high speed. Because the collision occurred simultaneously on a concentric circle, the metal jets fly to a center portion and converge from all of the directions, and collide at center axis. It is expected that flying velocity of the metal jets attains at an order of 1 TPa must be obtained at the center axis. In this paper, this novel system on the generation of the extremely high shock pressure is offered. Experimental results performed will be also reported.

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This paper describes a new seam welding technique and its experimental results. When an impulse current from a capacitor bank passes through a flat one-turn coil, a high-density magnetic flux is suddenly generated in the coil. Eddy currents are induced inside the overlapped ends of Al-Cu sheets (thickness 0.5 mm) placed in the coil. The ends can be joined both by the Joule heat generated in them and by the magnetic pressure applied onto them. A bank energy required for seam welding an area 5 mm×100 mm is less than 3 kJ.

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A method for shock consolidation of hard powders at elevated temperature is designed and employed for the compaction of diamond and related material powders. At a temperature above 1100℃, diamond and other compacts are well consolidated due to softening the powders at elevated temperature. The hardness of the diamond compacts show high Vickers hardness which correspands with the original powder material. Mixed diamond + c-BN powders are also consolidated at high temperature and well consolidated showing high hardness.

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In recent years, higher accuracy processing becomes possible by the development of cutting technology. However, the cutting of the corner is difficult yet. In this study, we are trying to develop the MC-EDM hybrid processing system that removes the corner by EDM after the cutting on the same machine, and examine the Mist-EDM processing with the cutting oil This paper describes on the possibility of machining of corner with Mist-EDM.

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Radial distribution of a magnetic flux density between a coil and an aluminum plate with a hole is measured and forming conditions on bore flanging of an aluminum plate by an electromagnetic forming is investigated experimentally. The magnetic flux density is not uniform along radial direction of the coil. The charging voltage, the length of flanging part and the corner radius of a die have a large effect on the bore flanging process. When the length of flanging part is short, the bore flanging above 90^0 can be easily obtained.

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Electromagnetic forming is suitable for tube forming. However, there are few reports on electromagnetic curling. In this paper, experiment and FEM analysis on outside-curling of Al tube (A1050) by electromagnetic forming are performed. The results show that electromagnetic forming is applicable to outside-curling, and die shape, forming length and magnetic pressure determine the forming limit. Experimental results for the deformed workpiece agree with those of FEM analysis.

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A new method of explosive welding is proposed. In this process, the underwater shock moving on a flyer plate is used for accelerating the flyer plate instead of the detonating wave moving on it in a usual explosive welding method. This paper deals with the new method and some experimental results by this method.

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In blanking a circular hole under impulsive pressure, computational simulation by using finite-difference scheme was attempted to examine the edge shape and its results were compared with the experimental results. Three kinds of metal plats 1mm in thickness, aluminium, copper and SUS304 , were employed in the experiments. The experimental results showed that the edge shape differed sharply with different mechanical properties of specimens. The edge shape based on the numerically simulated results showed about the same tendency as the experimental results. So, the effects of each parameter of the mechanical properties were discussed by the numerical simulations

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It is difficult to machine the corner of the metallic mold by cutting and grinding. But, the corner processing of the metallic mold by EDM is effective. In order to use EDM, it is necessary to carry work piece from cutting machine to EDM machine. It will be big merit if the corner processing of the metallic mold by mist EDM can be processed on the same cutting machine. In this experiment influence of mist supply method was studied as a basic research to construct mist EDM and cutting hybrid machine.

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Behaviors of monosized spherical copper powder particles of 550 μm average diameter in the powder compact was observed under optical microscope during one pulsed electric discharge for 500ms. The morphologies of necks between powder particles were observed under scanning electron microscope and diameters of necks were measured. It was confirmed that if the spark occurs or not depends on the pressure and pulsed current density. The spark at the interparticle contacts occurred more frequently, as the pressure was smaller and the current density was larger. Each particle was joined together by melting where the spark occurred. However, regardless the spark was observed or not, the necks were formed at the interparticle contacts and diameters of necks increased with increasing pulsed current density. It was suggested that microscopic spark, melting and vaporization occur due to extremely high temperature by the local heat generation at the interparticle contacts in the initial stage of compaction.

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In this report, metal balls are superficially placed keeping appropriate distances with each other in order to maintain human eye visibility. Then, by applying electric current in order to create spark discharges and photographed the routes of discharges.Based upon the traces of spark discharges as photographed, the amount of electric'current that flows between balls does not necessarily depend upon the distances between the balls. It can also be observed that the spark discharges are not just happening partially but extend over the entire surface. By giving spark discharge current to the powder, we obtained the correlation between the amount of electric current and the diameters of test materials created. As an application example, the spark current was applied to the metal powder in the isostatic rubber press and the powder was sintered in 10 plus several seconds. This report also explains such data including the equipment used.

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the spark plasma sintering process shows the power for the development of the porous material and functionally material, on the one hand, photo-catalyst function attracts big attention in the environmental protection, purification field, so, the compacting of the titania porous material which has photo-catalyst function was tried by using the spark plasma sintering process, as a result, the titania porous material can be compacted in the spark plasma sintering process.

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Cu-Sn-MoS_2 composite layer was formed on the sliding surface of automotive component "rackguide" by pulsed current pressure sintering process. The substrate of the rackguide was sintered simultaneously with the mixtured metal powder corresponded to A2014 aluminum alloy. Microstructure observation by OM and SEM, rockwell hardness test, friction test and dimensional measurement of the sintered specimen were carried out. Main results obtained were as follows : (1) Neither cracks nor pores were observed in the sliding surface and the substrate of the rackguide. (2) The shape of the top on the rackguide was deformed by forming of the sliding surface layer on the rackguide. But this deformation of the rackguide could be corrected by using the plastic forming process.

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Eutectic composites consist of twined single crystals and are prepared by solidification of the melt. The properties of eutectic composites are different from those of conventional composites. The high strength of oxide eutectic composites is not lost near 1500℃, and composites such as Al_2O_3-ZrO_2 and Al_2O_3-Y_3Al_5O_<12>(YAG) can be used for ceramic turbine blade. The synthesis of a eutectic composite free from cracks is carried out by unidirectional solidification. This solidification is inadequate to produce large and near-net-shaped materials. Eutectic powders of A12O3-YAG were prepared from the eutectic composite melted by arc discharge. The powder was classified into 3 - 44, 44 - 64 and 64 -124 μm, and consolidated by the spark plasma system (SPS).

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P/M Al_<92>Fe_3Cr_2Ti_2Mm_1 alloy prepared by the powder metallurgy (P/M) process have high tensile strength exceeding 600 MPa, high-elevated temperature strength exceeding 300 MPa after holding for 100 hr at 573 K. In this work, structural and mechanical properties of the SPS Al_<93>-xFe_3Cr_2Ti_2Mmx (X=0.5, 1.0) alloys prepared by the spark plasma system (SPS) were studied. The results were as follows: compressive fracture strength of 750 MPa, plastic elongation of 4.0%, Vikers hardness of 195 at room temperature and 110 at 573 K.

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Apparatus and method to perform etching and sputtering of continuous thin-film on substrate of various kinds by Penning discharge sputtering has benn developed and evaluated. The vacuum vessel has been composed of discharge chamber and specimen chamber. In this apparatus, selection of etching and sputtering modes are made by a change of anode position. Therefore, it has the features in which that it etches on the substrate first and deposits a thin film of the desire on the newly formed surface which continuously etches is possible. In this study, the glass was used for the substrate, and silver and copper were used as a sputtering material. The argon gas was used for the discharge. The relationship between the deposited film thickness for vapor deposition time and gas pressure was inbestigated.

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A photovoltaic cell consisting of Au/ Amorphous Carbon (a-C:H) films / n-Si (p-Si) /In-Ga films was prepared. The a-C:H films were deposited on n-type and p-type single crystal silicon substrates by two methods : a) RF-plasma CVD with an undiluted methane gas; and b) RF-magnetron sputtering using a sintered diamond target. Under the light illumination (Xe arc lamp at 100 mw/cm^2), this carbon cell shows a photovoltaic behavior with short circuit photo current of 0.3 mA/cm^2 and open circuit potential of 300 mV. It was found that the photovoltage significantly depends on the thickness of a-C:H films and corresponds to the maximum at about 200 nm. Moreover, a fiber type PV cell (we call it solar fiber) consisting of a tungsten wire / n a-Si:H / i a-Si:H / a-C:H / Al was fabricated. This solar fiber shows open circuit potential of 45 mV at an illumination level of 100 mW/cm^2.

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This paper describes characteristics of DLC ,c-BN and B-C-N films grown from diamond,c-BN powder and diamond/c-BN powder mixture targets respectively. Firstly, DLC films were prepared on silicon and silica glass substrates by DC-magnetron sputtering using a sintered diamond (polycrystalline diamond, PCD) target. It was found that the optical transmittance of the DLC film grown from the PCD target with an Ar ion laser beam (wave-length = 488 nm, 514.5 nm) was about four-fold larger than that grown from a graphite target. Secondly B-C-N films were prepared from diamond and c-BN powder mixture target. The B-C-N films didn't show the significant weight change under the heat treatment test at 500 ℃ in the air, and the hardness of the B-C-N films remained constant up to 500℃, whereas the DLC films were disappeared after the test. These results suggest that the B-C-N film has the potential to be applied to the tribological coatings under relatively high temperature conditions.

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In order to improve wear resistance and adhesion between DLC films and stainless dies, the mechanical properties of the DLC films which were deposited on SUS630 substrates have been investigated. It was clearly shown that adhesion strength as well as wear resistance of the die significantly improved when high-voltage pulse pretreating was applied before DLC deposition. The DLC film showed good wear resistance in the actual extrusion experiment using clay materials.

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We developed a piezo-resistive type thin-film pressure sensor composed of an alloy of manganese, nickel and copper in order to measure the oil-film pressure accurately on the sliding surfaces in internal combustion engine. This sensor was fabricated by physical vapor deposition, which deposits a sensor film of 3-6 micrometers thickness directly onto engine plane bearing. This sensor can measure the oil-film pressure without changing the bearing shape and without impairing the rigidity of the bearing housing. However, the characteristic of this sensor was impaired when it was exposed in high temperature. In this study, we reported the structure of the thin-film pressure sensor, the measurement result of the oil-film pressure in engine main bearing and the analysis result for the effect of the sensor alloy by ESCA(XPS) in order to investigate the cause of the sensor characteristic deterioration by the high temperature.

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Lubricant is harmful in metal forming process from the ecology point of view. In this study, a new combination blank holder vibration and fuzzy adaptive control was proposed and implemented in order to reduce friction effect with no lubricant in deep-drawing operation. The fuzzy adaptive control scheme used in this study is that minimum blank holder force(BHF) is momently applied to control wrinkles occurred during deep-drawing process. The deep-drawing experiment was carried out using mild steel and the forming load and energy were compared with four conditions such as constant BHF, BHF vibration, BHF fuzzy adaptive control, BHF vibration and fuzzy adaptive control. As a result, a new combination control scheme is seen to be considerably effective to reduce the forming load and is expected as a dry forming technique.

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In this study, we proposed a new formabiliry testing method for hydroformed tubular products. This test was simulated and evaluated by the finite element method (FEM). The nonlinear explicit FEM program, LS-DYNA was used in the simulation. This new method is performed by changing the cross section of a circular tube to a tapered box shape. In order to determine the suitable testing conditions and the die geometry and dimensions, process parameters (friction coefficient μ, axial penetration parameter m) and material variables (n-and r-values) were taken as the influencing factors in the simulation. As a result, we found that the nominal die-fitting ratio (NDFR) obtained by measurement of the maximum tube expansion is an easy evaluation parameter. The suitable die angle, at which the die-fitting ability can be characterized, is predicted to be between 10 and 15 degrees. The possibility of combination with a taper die and a kite shape is shown as a hydroforming test for the various complicated hydroformed parts.

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As well known, the application of plating treatments to a product shaped by deep-drawing into a battery case for a portable telephone from a disc-shape sheet usually accompanies difficulty, since the case has a narrow and high depth. To solve this problem, the application of a plating treatment to a sheet before deep-drawing is a key point. Moreover, keeping the plated film not to come off during deep-drawing process is also important. In this study, the Ni-plated sheet having diffusion layers between the Ni plate and a base steel was deep-drawn by 12 steps to manufacture a battery case. Mechanical properties and surface conditions of the deep-drawn sheet were investigated. Results obtained in this study show that a good Ni plated battery case was successfully manufactured.

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In order to increase stretch formability of the magnesium-based alloy AZ31 sheets, the hydraulic bulge forming was carried out with the rolled sheets and the forged sheets with thickness of 1.0 mm. The forged sheets with thickness of 1.0 mm has been forged from the rolled sheets with thickness of 3.0 mm at elevated temperature since grain size would be refined in the during reduction. Consequently, in the bulge forming at 473 K, bulge height in the forged sheets have been twice as height as the rolled sheets, and this has been nearly as height as bulge height in the rolled sheets at 573K. What's more, the forming in the forged sheet has enabled to form at lower temperature than the rolled sheet.

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The fatigue behavior of cemented carbide die under service load in the multistage cold forging of steel was investigated. It was found that the fatigue cracks do not initiate at the stress concentration position. TEM images at the position near the crack tip show dislocation exists in the WC particles and Co phase keeps fee arrangement. EPMA observation of fractograph shows that the volume of WC is about 70-80%. It can be concluded that the fatigue crack propagates in the WC particles and along the interface between WC particle and Co phase.

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The methods of manufacturing a clad plate being used now in industry is the cold or heat rolling bonding, explosion bonding, and diffusion bonding. These methods are disadvantageous because they are not suitable for thick and wide plates. Also, conventional bonding processes are strongly dependent to metallurgical properties of materials, requires higher energy, and are difficult for brittle materials. The combination of materials with big difference of yield stress may exhibit another difficulties in conventional bond processes. A new method of manufacturing a clad plate using Metallurgical Mechanical Bonding is proposed in this paper. It uses localized plastic flow that occurs in bounding area. As a first step of investigation, bonding characteristics are examined and discussed.

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Continuous Hot Rolling system with Electric Resistance Heating is developed. This system aims to realize accurate and uniform control of temperature of materials, utilizing automatic compensation for temperature due to thermal conductivity to temperature. Flexible control of microstructure after hot forming will become possible by proposed system, as the simultaneous control of temperature and plastic deformation can be easily made. Basic characteristic of Continuous Hot Rolling system with Electric Resistance Heating(CHR-ER process) is investigated through a series of experiment using stainless steel.

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The planer anisotropy of rolled sheet is one of the most important parameter in sheet forming as it is dominant to the formation of wrinkles, defects and formability in sheet forming processes. As the anisotropy of sheets are generated and controlled by rolling processes and succeeding continuous annealing, precise analysis for the evolution of texture is requested to design rolling schedule and annealing schedule. Here, the effects of rolling schedule to texture evolution is investigated in order to have general information how rolling condition is affecting to r-value of rolled sheets. Texture evolution of cold steel sheets with BCC lattice according to the difference in imposed reductions are shown and discussed.

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Three-dimensional FEM analysis for rolling processes is developed. It is based on finite deformation theory using co-rotational formulation. Three-dimensional FEM analyses of cold rolling processes are requested to predict 'shape' or flatness of rolled sheet, then the precise three-dimensional analyses of residual stresses are needed. Present report describes the method we used for developing an elastic-plastic code for analyzing such rolling processes, and several results of simulations are shown and discussed.

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This study has been performed to examine the deformation behavior and microstructure change in the spinning process of a magnesium alloy pipe. Spinning forming was conducted by an NC control machine at 300 ℃ with main shaft rotational frequency 300 rpm and feed per revolution 180 mm/min. Test specimen was a magnesium alloy pipe with outer diameter 100 mm and wall thickness 3 mm. Spinning forming was successful to form a dome part of pressure gas cylinder. Variation of wall thickness was examined in deformed part. Grain size refinement was confirmed by microstructure examination.

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This paper describes the influence of the Al,Zn and Mn contents on extrudability of magnesium alloy. As Al and Zn content increase,extrusion speed limit becomes smaller because of the surface cracks. And it became clear that extrusion pressure of the magnesium alloys are not so higher than 6063 aluminum alloy. The influence of Al, Zn and Mn contents on extrusion pressure has evaluated as experimental equation.

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Recently, the development of aluminum car body which employs aluminium space-frame structure has been paid strong attention in terms of it's light weight as wel as safety preservation . In this study, a novel extrusion equipment, that uses a taper mandrel and four movable dies, was developed to obtain a smooth and valuable cross-section to omit the secondary process of aluminum space frame. By using this equipment, extrusion experiments of aluminum alloy are carried out, and variable shape square pipes with extrusion ratio of 2-10 are produced.

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The purpose of this paper is to clarify the mechanism and lubricating effects of outflow behavior of lubricant trapped in pits by using a rolling-type tribometer and strip-ironing type tribometer. The pits regularly arranged on a workpiece surface were produced by coining a die surface topography. Experiments results show that the lubricant trapped in pits is difficult to enter into contact interface when the seal condition of surrounding the pit is tight. The lubricating improvement effects of pits are largely dependent on the lubricating regime in the blank region and disappear rapidly with the shift of the lubricating regime in the blank region from the boundary lubrication to the hydrodynamic lubrication.

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In order to use the Japanese cedar, studies of compression wood are making progress. It has been cleared that compression wood improve on the strength, rigidity and hardness. In this study, to make the bending and compression wood, Japanese cedar is pressed on the several conditions (combinations of plasticizing and punch speed). The results are summarized as follows. (1) Forming the bending wood need irradiation time at least 60 seconds in microwave. (2) The probability of occurrence of fractures is proportional to punch speed. But inclination angle of annual rings control the occurrence of fracture. (3) The strength of the bent wood is improved by compression.

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In this paper, new compressed-wood manufacturing process 'Roll press method' was proposed. In order to manufacture compressed-wood column or long sheet, application of rolling mill for compression process had been studied, although there were still two problems for application of rolling mill. One was occurrence of cracks or delaminations that were arisen from local deformation along roll. And another one was dimension recovery. We designed devices to prevent these problems and developed new compressed-wood manufacturing process 'Roll press method'. Roll press method enable manufacturing compressed-wood without crack or delamination, and dimension recovery. We manufactured compressed-wood by roll press method and did static bending test. Bending test result showed positive correlation between bending strength and compression ratio. These results mean effectiveness of roll press method and denote possibility for manufacturing compressed-wood column or long sheet.

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In cutting process, it is no easy to find better cutting condition, because it is necessary to do many cutting tests and to do experience for cutting. It spend many cost for many cutting test, and cutting test by new cutting condition have difficulty and dangerous because the tool often break or the vibration of cutting machine often occur. So, we propose the new system which helps the user to find the better cutting condition by using cutting process simulation software and optimization technology. As the first test of this system, we try to solve the optimum problem of maximum cutting material removal rate. Finally, we show the availability of this system.

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To clarify fracture mechanism of cutting process with wedge-shape tool, molecular dynamics simulations are conducted. Al single crystalline is dealt with and variation of cutting force, morphology of fracture and stress distribution are investigated. Then, effects of angle of wedge-shape tool tip and orientation of crystal on them are considered. Slip direction and plane have large influences on stress distribution and deformation morphology. Constrains to atomic slip result from the shape of tool and orientation of crystal. It is shown that atomic slips cause compressive stress at inner region of specimen near cutting tool and this is the main source of fracture.

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Powder metallurgical aluminum alloys exhibit high strain rate superplasticity due to the very fine grains obtained by dynamic recrystallization. The superplastic behavior in dynamically recrystallized alloy is different from that in conventional superplastic materials. From the micro structural point of view, grain boundary characteristics may affect the deformation mechanism. However, the influence of microstructural change on deformation mechanism during superplastic flow has not been clarified yet in dynamically recrystallized alloys. In this study, deformation behavior during deformation attributed to grain boundary characteristics was investigated. The material used for this study was P/M7475 (7475 aluminum alloy processed by powder metallurgy). Grain boundary characteristics were inspected by orientation imaging microscopy (OIM). In P/M7475, the dynamic recrystallization occurred during the deformation. This microstructural change influences deformation mechanism during superplastic deformation.

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This study deals with the stress analysis and the strength evaluation of an adhesive butt joint combining a coupling collar when the joint is subjected to an internal pressure and a temperature change. The stress distributions at the interface between the adherends and the adhesive in the joint are analyzed by using the axisymmetric finite element method (FEM). In addition, the rupture test of the joint was carried out by applying an internal pressure and a temperature change to the joint. From the numerical calculation and the experiment, strength of adhesive butt joint combining a coupling collar is estimated by using the stress distribution at the interface obtained from the FEM analysis.

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Influence of strain rate on fracture toughness characteristics of an acrylic adhesive were investigated using DCB joints under Mode I loading-unloading condition. The DCB joints were fabricated by using an acrylic adhesive and adherends of steel. The unloading compliances measured were found to be much greater than the theoretical values. The elastic-plastic fracture toughness J values showed an approximately linear increasing tendency with increasing crack growth. Increasing of strain rate results in increasing of fracture toughness G_Ic and elastic-plastic fracture toughness J values.

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Crack deflection in the adhesive layer was investigated for adhesively bonded single lap joints. Cracks occurring at both bond termini interfacially propagated about 0.4 〜 1.4mm (critical length: a_1) away from the lap ends. When the cracks grew to a_t in length, they changed their direction into adhesive layer and propagated cohesively. The stress distribution for various geometric configurations of single lap joints was analyzed by using FEM. A local mix-mode ratio between Mode I and Mode II for interfacial cracks was defined based on the strain energy release rate for each mode. The FEM results show almost the same G_T curves for any geometry of single lap joints if the cracks were supposed to propagate interfacially. The calculated results also showed that the Mode I component in G_T was decreased when the cracks changed their direction. The crack deflection mechanism is related to the change of mix-mode ratio in G_T.

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Bonding technology is good for lightening, saving energies, rationalization of production process, and dispersing stress concentration. In reality, the adhesive layer is subjected to cyclic loading, so it is necessary to study adhesive strength under not only static loading but also cyclic loading. In this study, cylindrical butt type specimen and XD911 epoxy adhesive are used. Both tests under static and cyclic loading are done under combined tensile with shear stresses. It is found that Modified Adhesive strength surface by taking stress singularity into consideration, corresponds to fatigue failure surface.

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