An ultrasonic method for measuring a two-dimensional temperature distribution on a material surface is presented. The method provides non-contact measurements of surface temperature. The principle of the method is based on surface acoustic wave (SAW) measurements using a laser-ultrasonic technique and its two-dimensional scanning on a material surface. The surface temperature distribution is basically determined by an effective method consisting of SAW measurements and an inverse analysis coupled with a one-dimensional finite difference calculation. The ultrasonic method has been applied to the surface temperature measurement of an aluminum plate whose single side is being heated. The surface temperature distributions determined by the ultrasonic method almost agree with those measured using an infrared camera.

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Spot-welding technique is widely used in the various fields of engineering and industries. Since the size and quality of the nugget which is melted and re-solidified part of a welding are closely related to the strength of the welded structure, it is important to estimate the diameter and mechanical property of the nugget quantitatively. In this work, an air-coupled ultrasound technique employing focused transducers has been used for non-contact measurements of a spot welding. Transmission C-scan measurements were performed using a pair of focused transducers operating with tone burst waves at 0.4 MHz. Signal processing techniques, an averaging, a band-pass filtering, and a matched filtering are used to improve the signal to noise ratio of the measured results. It has been found that the C-scan images using the matched filtering have a high signal to noise ratio even though a small number of data is used for averaging.

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In this work, an application of the ultrasonic method to internal temperature measurements of materials during casting has been studied. The principle of the method is based on the temperature dependence of the velocity of ultrasonic wave propagating through a material. An inverse analysis coupled with a finite difference calculation is used to determine a one-dimensional temperature distribution. An attempt to monitor both temperatures of a solidifying alloy and a die during casting process has been made. A low melting-point alloy is employed as the melt. Ultrasonic pulse-echo measurements are performed and the changes in the transit times of the reflected echoes through the die and the alloy are continuously acquired, and then the temperature distributions inside the die and the alloy have been estimated during the casting process.

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A fundamental study was carried out on an application of an area detector to neutron stress measurement. A neutron image plate (NIP) was used in this experiment to obtain neutron diffraction rings of polycrystalline steel specimen. The diffraction data were stored on a NIP and were converted to digital image data. Strains were obtained from these data and were analyzed to determine stress using the cos a method. Though these stresses were different from applied stresses, they increased in proportion to applied stresses. Namely, the differences between measured and applied stresses were almost constant during loading. Based on these experimental results, two practical methods were proposed for determining exact stress using a NIP. The stresses obtained using one of these methods showed good agreement with applied stresses. From these results, it is concluded that we can obtain mean stress in materials using neutron diffraction technique with an area detector.

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Railway rail is fatigued by rolling contact with the wheel, and crack initiates on the surface. The crack that initiated on the surface progresses and may reach an accident to be broken. It is known that residual stress influences the initiation and the later crack growth rate of the crack of the railway rail, but the details are not found. In this study, the authors aims at clarifying the residual stress of the railway rail heads by X-ray diffraction. The test samples were taken from railway rails used in a service line in Japan. The X-ray measurement was conducted using the standard parallel beam optics.

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This paper describes about the application of X-ray diffraction technique to the butt weld of thick plates. Weld of a large steel structure is conducted to a cold cracking induced by a residual stress. The PWHT prevent the cold cracking by a residual stress. There are few reports on the effect of PWHT on the residual stress relaxation. Measurement was made on the surface of butt weld of thick plates. As a result of the experiment, it was found that the butt welding residual stress was relaxed by PWHT.

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共焦点顕微鏡(confocal microscope)は従来の光学顕微鏡よりも高い空間解像力を容易に得ることができることから,近年医療用,粗さ測定,細胞の観察,食品の観察などに用いられている.しかし,共焦点顕微鏡はレンズまたは試料をx,y,zの三方向にスキャンしながら画像を撮影するため,三次元形状を計測するのに長い時間を要する.このため,ニポウディスクやマイクロレンズアレイを利用して,計測時間の短縮を実現している製品もあるが,これらは複雑で高価になってしまうため,なかなか手が出ないこともあるという.そこで,本研究では共焦点原理とラインカメラを利用し,線状のレーザを披測定物に当て,線状の反射光をラインカメラで読み取ることでスキャン方向を一つ減らし,三次元形状計測にかかる時間を短縮するための手法を検討した.この手法が有効であると示すことができれば,測定時間の短縮により,動いている物の観察を行ったり,製品の全数チェックが容易になる.本研究においてはレンズ,モータ,コンピュータなどの制約から従来よりも高速で測定することはできないが,あくまでも共焦点原理とラインカメラの組み合わせが有効であることを確認することが目的となる.まだ完成にはいたっていないが,現在速んでいるところまでの問題点や効果等を検討・報告する.

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It is known that stress-strain relations of a material can be obtained using a nano-indentation technique with a spherical tip. In this work, the effects of the experimental parameters on the accuracy in estimating stress-strain curve and yield stress by multiple continuous loading method using a load-controlled nano-indentation. Experimental parameters such as initial indentation, indentation time relating to deformation rate, holding time at maximum loading, and unloading ratio are changed and the influence on the obtained result is investigated. It has been found that the indentation time and the holding time seems to affect the stress-strain curve and yield stress.

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The powder metallurgy is advantageous for near net shape manufacturing.. However, because of an increasing demand for the parts with more complex shapes in recent years, some material removal processes are necessary for formed parts. As such, the machinability of sintered iron is an important topic. The metal removal process used for powder metallurgy parts is usually applied to sintered compacts. However, a removal process for the powder compact prior to sintering (referred to as "green compacts"), which is known as green machining, has been attracting attention lately. In order for green machining to gain full acceptance, it is necessary that sintered parts produced by this method have the same mechanical strength as sintered parts produced by conventional sinter machining. In the first study, we compared the mechanical strength of a cylindrical compact formed from ferrous powder, which was drilled and then sintered, with the mechanical strength of a part that was sintered and then drilled to produce the same shape. The mechanical strength was evaluated according to the radial crushing strength test (JIS-Z-2507). In the present study, a test piece was produced with PVA (polyvinyl alcohol) and agar was added to the ferrous powder as a binder. It was found that the cutting force (thrust and torque) and the chips from the drilling processes on green compacts produced using PVA or agar as the binder were considerably smaller than the results of a green compact made of ferrous powder alone.

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Spark Plasma Sintering (SPS) can consolidate compacts at lower sintering temperature and in shorter sintering duration compared with conventional sinterings, such as hot-pressing or HIP. TiAl (Ti-48at%Al) compacts were sintered with changing sintering temperature and sintering duration. From tensile properties, the most suitable sintering condition of TiAl by SPS was investigated. And elevated tensile strength was also investigated.

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High porosity steel foams are produced by EPS space holder method and gel foaming method. And their heat conductivities, electrical conductivities are measured. As these results, stainless steel foams have high heat insulating properties, and they can achieve heat conductivity lower than 0.1W/mK. Also their heat conductivities and electrical conductivities have strong relation, and heat conductivities can be estimated from electrical conductivities.

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The foundation is cosmetic powder compacts for women, it occurrences accident as fractures if drops during occupied or carrying. In this study, the powder compact of foundation was molded under various conditions with the machine which we developed. And then, the fracture properties of the foundation in the fall test were evaluated when it drops from various heights. It occurrences the fracture as surface crack, internal crack, flaking of surface layer or disintegration, when it was received by high impact force. These fractures become remarkably in the rigid powder compacts.

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Dieless drawing is a flexible metal drawing technique accompanied by continuous necking using local heating and tensile load without any dies. It is difficult for this technique to realize high speed drawing, because the local heating cannot be achieved and the strain rate increases in high speed drawing. In previous study, the dieless drawing with non-local heating is carried out by means of effective control of drawing path. In this study, the effect of drawing speed and heating band on drawing limit is investigated from viewpoint of strain rate during deformation for dieless drawing with high speed. As a result, it is found that dieless drawing limit decreases with increasing strain rate on high drawing speed. Improvement of drawing limit is achieved by the decrease in strain rate due to increasing heating band.

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Cu and Fe shape-memory alloys, as well as Ni-Ti shape-memory alloys, have been developed thus far ; however, their workability is poor and it is difficult to accurately control their transformation temperature. An attempt has been made to improve the drawability of shape-memory alloy wire by conventional wire drawing and roller die drawing. We prepare Fe, Ni-Ti and Cu shape-memory alloy wires. The results are summarized as follows, 1) Under optimum drawing conditions, the drawing limit of Ni-Ti shape-memory alloy wire could be raise by up to 70%. 2) By removing the brittle layers on the Fe alloy wire surface, thereby, the drawability can be improved. 3) The shape-memory alloy wires obtained are expected to be applied to various fields, such as springs that can be used as actuators, and washers for easy-release screws.

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To form magnesium alloy sheets without heating, friction stir incremental forming process was developed. AZ31 and AZ61 sheets with 0.5mm or 0.7mm thickness were used and formed into frustum of pyramid shapes. Tool rotation rate, tool feed rate and half apex angle of pyramid were changed. Not only formability but also hardness and tensile strength of formed part were measured. From the experimental results, AZ31 sheet with 0.5mm thickness formed into a frustum of pyramid shape with the half apex angle of 25° by the developed method showed 137% elongation, and its tensile strength was about 10% higher than that of not formed one. AZ31 sheet with 0.7mm thickness and AZ61 sheet with 0.5mm thickness were also formed into a frustum of pyramid shape with the half apex angle of 45°, successively.

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Since aluminum alloy sheet metal have strong mechanical features such as low Yong's modulus, low ductility and strong initial anisotropy (high Lankford value), it remains one of the most difficult materials to predict the final shape of springback. In order to solve the problem, we applied the Yoshida-Uemori model for an aluminum alloy sheet metal s. In the present research, we have investigated the experimental Bauschinger effect and anisotropy of aluminum sheet metal. The calculated results show the great agreement with the corresponding experimental springback for aluminum alloy sheet. The efficiency of Yoshida-Uemori model for aluminum sheet metal is proved.

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This paper reports on the cutting characteristics of a polycarbonate (PC) worksheet mounted on flexible underlays by wedge indentation. In order to investigate the effect of underlay stiffness on sheared profile of PC worksheet, an underlay stiffness in thickness direction ku was varied by introducing the ku=Eu/tu as the underlay Young's modulus Eu by the underlay thickness tu. On the experimental works, we found that the underlay mechanical properties affected the cutting load response and deformation features of the PC sheet. Through the experiment and FEM simulation, the followings were obtained : the deformation profile of PC sheet remarkably depends on the stiffness ratio of underlays, when the stiffness ratio is less than a certain value.

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Asymmetric plunge cutting by using grooved knife edge plate was proposed for advanced die cutting of a polycarbonate (PC) sheet. By varying the tip angle α_U and the tip thickness wv of knife edge in the counter plate, and combining a standard steel cutting rule of 42 degree center bevel blade, a cutting load response of PC sheet was investigated and also that deformation was observed through a CCD camera. Through this works, the followings were found : 1) there were two deformation modes of sheared profile. 2) the tip thickness W_U was a primary factor, compared to the tip angle of α_U. 3) the equivalent wedge angle effect was revealed with respect to the upper/lower angles α, α_U, while the PC sheet was bent up by the lower knife indentation.

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The downsizing of the electronic devices has been achieved by downsizing of the electronic power modules and the circuits for high-frequencies. Those modules require the more miniaturizations in the solenoid parts, e,g, choke coil, or transformer. The so-called micro solenoids are expected to be made by winding the ultra-fine electronic wire with diameter of several tens of micrometers. But the ultra-fine electronic wire has less tensile and bending strength and melt during the conventional soldering process. Therefore, besides the ultrasonic bonding and the soldering, a new fixing method is developed for the ultra-fine electronic wire. The proposed method is called the micro-mechanical joining, by which the ultra-fine wire is mechanically held to the electronic terminal. The detailed method including the shape of the terminal and the protocol is described in this article. The smallness in the wire distortion is shown. The joint strength tests are conducted and the enough strength comparable to that of the base metal wire is obtained.

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Mechanical clinching is a mechanical joining method that has been attracting considerable attention as an alternative to spot welding or riveting, because of the many advantages it offers in assembling aluminum panel parts. However, the applications of this method are limited because it affords low peeling strength ; therefore, in order to increase the applicability of this method, it is necessary to improve the peeling strength afforded by it. In this study, a new method of mechanical clinching was devised whereby high-frequency ultrasonic vibration is applied to work pieces in a vertical direction. This vibration generates friction between the work pieces, and adhesion force is improved by destruction of oxide film. As a result, the peeling strength of ultrasonic assisted mechanical clinch is improved by 30 % compared with no ultrasonic assisted mechanical clinching, and improved by 95 % compared with the strength of general mechanical clinching : no ultrasonic assist and no degreasing condition.

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Though there are lots of tribometers for thin hard coating, there is few tribometer that can duplicate actual processing. The tribometer we developed is all-new testing machine that can measure tribo-characteristics by duplicating warm-ironing tests. In this paper, we report detail of developed tribometer and basic experiment results.

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The interface of seized interface between die and workpiece was observed in order to understand mechanism of seizure during hot hummer forging of carbon steels. In this study, S55C and SKT4 were used as workpeices and dies, respectively. During hummer forging to form the T-shape cross-section, seizure between die and workpeice was obtained. Die surface by removing seized workpeice can be classified into 4 regions from the upper surface of die, (1) free-die surface area, (2) dimple pattern area, (3) striped structure area, and (4) dotted structure area. Adhesion between workpiece and die is caused by dimple pattern area and striped structure area

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TIG welding process is often used to join thin metal plates because of the stability of arc compared with the other arc welding processes. However, the tungsten electrode tip of the TIG welding torch considerably consumes during the welding due to the high temperature of the arc and the oxidation by surrounding air. As a result, the shape of the electrode tip changes and the arc becomes unstable. Accordingly, in order to realize stable welding, administration of the tungsten electrode tip is important. Since the arc is essentially unstable, sometimes it becomes unstable by some other factors. On the contrary, the laser beam has extraordinary stability and directivity because of the nature of the light beam. Therefore, stabilization and control of the unstable TIG arc by the laser beam is tried. In this study, the feasibility of stabilization and control of welding arc by laser beam is studied using hybrid welding process combining TIG arc and YAG laser with relatively low power.

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We have developed a microwelding technique using micro electric discharge. Here, two thin wires of 50 microns in diameter, an alumel wire and a chromel wire, were welded to make fine thermocouple by the above microwelding method. The two wires were fixed to butt their tips. Discharge was generated for about 0.5 seconds by applying 5kV to a tungsten needle placed above the tips. After repeated discharges, the tips were melted and a junction was formed. The butt angle is an important factor for the size of the junction. It was less than 2 times of the wire diameter, when the butt angle is greater than 100 degrees.

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Carbon-carbon composites were brazed to a pure titanium using a Ag-Cu-Ti filler metal (Cusil-ABA^<[○!R]>) at 830℃ for 60s or 300s in vacuum of 1.0×10^<-4> Torr. The microstructure of the brazed joint interface was observed through the optical microscope and the scanning electron microscope (SEM). By analyzing with the energy dispersive spectroscopy (EDS), the constituents' distribution at the brazed interface was measured. Those observations and analyses revealed that the yarns of C/C composites were disbanded into the carbon fibers, and that the carbon fibers were corroded. The titanium included not only in the brazing filler metal but also in the bulk metal which diffused into the molten brazing filler metal formed the carbide to corrode the C/C composites. The corrosion was more severe for the brazed joint made by a longer brazing time. These results suggest that the brazing time must be shorter to obtain the stronger brazed joint for C/C composites and titanium.

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The most suitable joining condition of porous aluminum and aluminum plate by spark plasma sinter-joining was examined. In addition, the effect of joining condition on bonding strength of jointed specimen was clarified. Main results are summarized as follows ; (1) It was possible to join porous aluminum and aluminum plate with joining temperature more than 723K by spark plasma sinter-joining. (2) The upper limit of joining temperature was 903K so that the local melting and high-temperature creep occurred. (3) The bonding strength of jointed specimen increased with increasing height reduction. (4) The jointed specimen was joined strongly with increasing joining temperature by disappearance of joined interface.

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In Aluminum alloy high pressure die-casting, controlling the mold temperature is critical to achieving high quality products, high productivity, and long operating life of molds. The temperature is controlled by the circulation of a fluid through flow channels made in the mold by drilling cylindrical holes and sealing excess parts. These straight flow channels do not function enough to cool the mold and they shorten the mold life, and on top of it, drill processing costs high and takes time. Our goal is to create free-formed flow channels which can efficiently cool the mold. We plan to make multiple parts of a mold to which we create flow channels freely by machining, and join the parts by solid-state joining. In this study, SKD61 steel plates were joined by SPS (Spark Plasma Sintering) method, and the mechanical properties of the joints were examined.

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Cruciform specimen method is one of tests evaluating fiber/matrix interfacial strength. The advantage of this technique is to eliminate the effect of stress singularity of the fiber end and the intersecting interface edges. However, a problem is remaining for the test ; i.e. the interfacial debonding initiation location is unclear. This is the most critical issue for evaluating the interfacial strength because stress state is different for individual location. Therefore, an analytical discussion is necessary to specify the debonding initiation location under a certain interfacial failure criterion. This paper focuses on where the interfacial debonding initiates from in a cruciform specimen having various cruciform arm angles. By combining analytical and experimental results, both the debonding initiation location and the interfacial normal and shear strength are clarified under assumed interfacial failure criteria.

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