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| 1.
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Aziz, Mohd Sanusi Abdul ; Furumoto, Tatsuaki ; Ueda, Takashi ; Abe, Satoshi ; Hosokawa, Akira ; Tanaka, Ryutaro
概要:
This paper investigates thermal and strain behaviour in the selective laser sintering process with a mixture of SCM, Cu
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and Ni metal powder. In-process monitoring of strain change and temperature at the base plate is proposed in order to investigate thermal and strain behaviour induced by selective laser sintering. A strain gauge was attached to the bottom surface of the base plate while a thermocouple was inserted at a distance of 2 mm from the top surface of the base plate. Changes in the strain and the base plate temperature were observed using an oscilloscope during the laser sintering process. The results showed that the development of strain within the sintered structure was affected by the processing temperature. Besides that, after the laser sintering process was completed, the strain value increased gradually and became constant as it reached room temperature. This strain value was found to correspond with the test model's deformation. In addition, the effects of laser scanning direction and laser energy density during the process were observed. Measurement of the test model's deformation was also carried out to discover its relationships to strain change and processing temperature. The results showed that the sintered structure produced by laser scanning of a sector along the width induced less residual strain, which resulted in less deformation. In contrast, both residual strain and deformation were found to be higher when the laser scanning was carried out along the length. Furthermore, when a low laser energy density was used, less deformation of the sintered structure could also be obtained. © (2012) Trans Tech Publications.
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| 2.
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藤本, 洋平 ; 宮崎, 利行 ; 佐々木, 敏彦
概要:
In this study, X-ray stress measurements of ferritic steel based on Fourier analysis are conducted. Taira et al. develop
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ed the cosα method for X-ray stress measurements using a two-dimensional X-ray detector. Miyazaki et al. reported that the cosα method can be described more concisely by developing the Fourier series (the Fourier analysis method). The Fourier analysis method is expected to yield the stress measurement with an imperfect Debye-Scherrer ring and there is a possibility that the materials evaluation is different compared with the conventional method, that is, the sin2ψ method. In the Fourier analysis method, the strain measured by X-rays is developed as a Fourier series, and all the plane-stress components can be calculated from the Fourier series. In this study, the normal stress calculation was confirmed. In addition, the Fourier-analysis and cosα methods were used for X-ray stress measurements during a four-point bending test on a S45C test piece, and the effectiveness of the Fourier analysis method was confirmed. It was found that the experimental results from the Fourier analysis and cosα methods were nearly identical. In addition, the measurement accuracies of both the methods were equivalent.
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| 3.
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丸山, 洋一 ; 宮崎, 利行 ; 佐々木, 敏彦
概要:
We have developed a novel residual stress measurement instrument based on the X-ray diffraction technique. An image plat
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e was used as the detector to sample the full diffraction ring. The image plate and the scanning unit were built into the one system. Compared with the traditional X-ray stress measurement systems, the physical size and weight of the instrument were significantly reduced. The instrument also has the capability to measure the distance from the specimen to the image plate. This capability contributes to improve the accuracy and simplicity of the stress measurement. The developed instrument was focused on measuring a ferrite sample and the acquired diffraction ring was analyzed using the cosα method. In the present work, we evaluated the accuracy of the measurement data from the instrument using a ferrite powder compared with strain gauge results obtained from four-point bending measurements.
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| 4.
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Hirose, Hajime ; Suzuki, Shinya ; Goto, Masahide ; Sasaki, Toshihiko
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金沢大学大学院自然科学研究科システム創成科学専攻<br />In depositing the TiN thin films to the substrate by Physical Vapor Deposition (PVD), it i
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nfluences the substrate interface. Change of the residual stress and the full-width at half maximum (FWHM) in each process of the TiN deposition of thin film was measured by the X-ray stress measurement. As a result of the X-ray stress measurement, there are no changes in the residual stress and the FWHM. It is thought that there is a difference in the penetration depth to the substrate of X-rays and Ti ion.
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| 5.
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Goto, Hiroshi ; Goto, Masahide ; Ejiri, Shoichi ; Horimoto, Yoshiaki ; Hirose, Yukio
概要:
The purpose of this study is to examine the effect of crystallite preferred orientation on the mechanical strength of TiCN thin films in highly compressive residual stress. TiCN thin films were deposited by PVD on JIS-SKH55 (AISI M35)
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steel. The applied substrate bias voltages were set for -50, -80, -100,-120 and -150V. Subsequently, residual stress and crystalline preferred orientation of these specimens were investigated by X-ray diffraction methodology. The crystalline preferred orientation in thin films was evaluated by the ODF calculated from pole figures. On the other hand, dynamic hardness test (DH) and scratch test were executed to evaluate the mechanical strength of thin films. In our study, it was observed that negative bias voltages had an effect on the preferred orientation. The orientation density at -120 V was the highest of all specimens. In addition, the value of scratch section area at -120V was the largest of all specimens. As a conclusion, the relation between the scratch area and the negative bias voltages corresponded to the relation between the preferred orientation and the bias voltages.
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| 6.
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Furumoto, Tatsuaki ; Ueda, Takashi ; Abdul Aziz, Mohd Sanusi ; Hosokawa, Akira ; Tanaka, Ryutaro
概要:
金沢大学理工研究域機械工学系<br />This paper deals with the reduction of residual stress induced during the selective laser melting wi
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th a mixture of ferrous based metal powder. To evaluate the residual stresses induced during layered manufacturing processes, a strain gauge is attached on the bottom face of the base plate. The residual stress within the consolidated structure is calculated from the amount of strain change measured by the strain gauge when the consolidated structure is cut with an end mill. The influences of base plate thickness and consolidated structure height on the residual stresses are investigated. In addition, the effect of pre-heating and post heating by a laser beam irradiation are evaluated. The results showed that the deformation of the base plate increased with the increase of the consolidated layer and the decrease of base plate thickness, and the deformation was flattened when the consolidated structure was completely removed with the end mill. The deformation was related to the induced residual stresses. The residual stress distribution within the consolidated structure in the z direction was extremely large at the top layer of the structure and the boundary between the base plate and consolidated structure. The residual stress at the first layer of the structure decreased when the base plate was heated before consolidating the deposited powder. The residual stresses decreased when each of the consolidated layers was repeatedly heated by the laser beam irradiation. © (2010) Trans Tech Publications.
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| 7.
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Seki, Katsuhiro ; Hashimoto, Munetoh ; Gotoh, Masahide ; Hirose, Yukio
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Recently, fine grain steel has been actively researched. However, as we know, the influence concerning the shot peening
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processing to fine grain steels has been few reported up to now. Therefore residual stress distribution near the surface of fine grain steel after shot-peening was measured by X-ray diffraction technology. Moreover, the hardening effect the distributed near the shot-peened surface was also estimated. The relationships between the effects of shot-peening and the grain size of material were discussed. Copyright © 2007 by The International Society of Off shore and Polar Engineers(ISOPE).
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| 8.
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増田, 秀夫 ; 鷹合, 滋樹 ; 比良, 光善 ; 広瀬, 幸雄
概要:
金沢大学大学院自然科学研究科<br />Ni-Co-P/α-Si_3N_4 composite plating excels in wear-and corrosion resistance. It is important to eval
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uate the residual stress due to the misfit of mechanical and physical properties between plating and substrate during the manufacturing and industrial using. However, in the case of plating specimen which have stress gradient, the sin^2Ψ method is not adequate to use because this material shows severely curved sin^2Ψ diagram. In this study, a fundamental investigation was carried out to apply the X-ray residual stress measurement of the plating material. Fourth kinds of specimens with different thickness of film were prepared. X-ray elastic constants were obtained using the non-liner analysis. Influence of the film thickness on curvature of 2θ-sin^2Ψ diagram was simulated. Residual stress in the plating layer was analyzed under the assumption that the stress state is equivalent biaxial. Some experimental results were observed: sin^2Ψ diagrams were severely curved, and shape of diagrams shows varied by the film thickness and X-ray penetration depth. There is the steep stress gradient in the direction of depth. As the results, X-ray elastic constants of all specimens were independent from the thickness of film. Therefore, the value is constantly. A value of residual compressive stress calculated form present method is grater than value of sin^2Ψ technique. Compressive stress decreased with the film thickness.
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| 9.
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Gotoh, Masahide ; Seki, Katsuhiro ; Shozu, M. ; Hirose, Hajime ; Sasaki, Toshihiko
概要:
金沢大学大学院自然科学研究科<br />The fine-grained rolling steels NFG600 and the conventional usual rolling steels SM490 were processe
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d by sand paper polishing and mechanical grinding to compare the residual stress generated after processing. The average grain size of NFG600 and SM490 is 3 μm and 15μm respectively. Therefore improvement of mechanical properties for such fine-grained steels is expected, it is important to understand the residual stress state of new fine-grained materials with processing. In this study, multi axial stresses of two kinds of specimens after polishing and grinding were measured by three kinds of analysis methods including cos-ψ method. As a result, as for σ33, the stress of NFG was compression, though that of SM490 was tension. © (2010) Trans Tech Publications.
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| 10.
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Mori, Toshiya ; Gotoh, Masahide ; Sasaki, Toshihiko ; Hirose, Yukio
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In this paper, a sample having 〈111〉 fiber texture near single crystal structure made by PVD was evaluated about texture
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states by the pole figure and about residual stress states by the new expression for X-ray stress analysis. As a result, about 6GPa compressive residual stress existed in the film. However, measurement planes of X-ray line were influence on each stress value. Copyright © 2007 by The International Society of Offshore and Polar Engineers(ISOPE).
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