start-ver=1.4
cd-journal=joma
no-vol=
cd-vols=
no-issue=
article-no=
start-page=
end-page=
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2024
dt-pub=2024
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Effect of artificial defect on tensile properties of thin titanium alloy wire
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=This study investigated the effects of artificial defects, introduced via focused ion beam (FIB) processing, on the tensile properties of thin titanium alloy wires (Ti-6Al-4V). Results indicated that the defective wires fractured when the net-section nominal stress reached the ultimate tensile strength of the smooth wires, probably because of localized stress concentrations relaxing due to plastic deformation around the defects. The effect of defects on tensile properties was classified into three regions based on the size of the defect area. In the case of small defects, wires fractured at the smooth area away from the defects where the cross-sectional strength was lower. In this case, the defects minimally affected the tensile properties. This is attributable to variations in the cross-sectional strength of the wire, which resulted in some sections with lower strength as compared with the defect area. In the case of medium-sized defects, the fracture strain decreased gradually as the defect area increased. Finally, in the case of large defects, the fracture strain was extremely small. The boundary between the medium-sized and large defects indicates the transition from plastic deformation to no plastic deformation in the smooth area.
en-copyright=
kn-copyright=

en-aut-name=SAKAMOTOJunji
en-aut-sei=SAKAMOTO
en-aut-mei=Junji
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=TADANaoya
en-aut-sei=TADA
en-aut-mei=Naoya
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=UEMORITakeshi
en-aut-sei=UEMORI
en-aut-mei=Takeshi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=OISHIKoyo
en-aut-sei=OISHI
en-aut-mei=Koyo
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

affil-num=1
en-affil=Okayama University
kn-affil=

affil-num=2
en-affil=Okayama University
kn-affil=

affil-num=3
en-affil=Okayama University
kn-affil=

affil-num=4
en-affil=Okayama University
kn-affil=
en-keyword=Ti-6Al-4V
kn-keyword=Ti-6Al-4V
en-keyword=Thin wire
kn-keyword=Thin wire
en-keyword=Tensile properties
kn-keyword=Tensile properties
en-keyword=Defect
kn-keyword=Defect
en-keyword=Focused ion beam
kn-keyword=Focused ion beam
en-keyword=Net-section nominal stress
kn-keyword=Net-section nominal stress
en-keyword=Fracture surface
kn-keyword=Fracture surface
en-keyword=Fracture strain
kn-keyword=Fracture strain
END

start-ver=1.4
cd-journal=joma
no-vol=153
cd-vols=
no-issue=
article-no=
start-page=107623
end-page=
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2023
dt-pub=202311
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Prediction of slip activity of crystal grains around semi-circular and semi-elliptical notches in thin-sheet specimens of pure titanium using formulated macroscopic stress distribution and crystal orientation
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Thin metal sheets and wires are important materials for various devices used in electrical, mechanical, and medical fields. With the downsizing of these devices, demand for thinner sheets and wires has increased. Amongst the many metals available, pure titanium has been attracting much attention for use in medical and dental devices because of its good biocompatibility in addition to its light weight and high corrosion resistance. However, thin metal sheets and wires are usually polycrystalline materials and, with the downsizing of materials, there is a loss of homogeneity during deformations. Inhomogeneous deformation becomes significant in thin sheets and wires, owing to the different crystal orientations and geometries of crystal grains. Furthermore, the shapes of such devices are not uniform, unlike, say, a simple rod. Therefore, macroscopic stress and strain concentrations should be taken into consideration when designing these devices as they affect the localization of deformation and the resultant fracture. In this study, semi-circular and semi-elliptical notched specimens made of thin-sheet polycrystalline pure titanium are subjected to tensile testing. Inhomogeneous deformation caused by crystallographic slip is observed near the notch root. Analysis of the crystal orientation and observation of the slip line show that the slip initiation in crystal grains is affected by the macroscopic stress distribution and can be predicted from the slip activity calculated from both the critical resolved shear stress on the slip systems and the resolved shear stress acting on prospective slip planes obtained from the macroscopic multiaxial stress distribution.
en-copyright=
kn-copyright=

en-aut-name=TadaNaoya
en-aut-sei=Tada
en-aut-mei=Naoya
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=UemoriTakeshi
en-aut-sei=Uemori
en-aut-mei=Takeshi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=SakamotoJunji
en-aut-sei=Sakamoto
en-aut-mei=Junji
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

affil-num=1
en-affil=Faculty of Environmental, Life, Natural Science and Technology, Okayama University
kn-affil=

affil-num=2
en-affil=Faculty of Environmental, Life, Natural Science and Technology, Okayama University
kn-affil=

affil-num=3
en-affil=Faculty of Environmental, Life, Natural Science and Technology, Okayama University
kn-affil=
en-keyword=Mechanical engineering
kn-keyword=Mechanical engineering
en-keyword=Microdevices made of thin metal sheet
kn-keyword=Microdevices made of thin metal sheet
en-keyword=Pure titanium
kn-keyword=Pure titanium
en-keyword=Deformation
kn-keyword=Deformation
en-keyword=Microscopic characterization and microanalysis
kn-keyword=Microscopic characterization and microanalysis
en-keyword=Plastic deformation
kn-keyword=Plastic deformation
en-keyword=Microscopic inhomogeneity and stress
kn-keyword=Microscopic inhomogeneity and stress
en-keyword=concentration
kn-keyword=concentration
en-keyword=Slip activity control
kn-keyword=Slip activity control
END

start-ver=1.4
cd-journal=joma
no-vol=143
cd-vols=
no-issue=2
article-no=
start-page=021502
end-page=
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2020
dt-pub=2020105
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Prediction of the Fracture Location by Tensile Tests of Gray Cast Iron Based on the Dimensional Changes of Graphite Flakes
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Gray cast iron has been used as a component in various mechanical parts, such as the blocks and heads of automobile and marine engines, cylinder liners for internal combustion engines, and machine tool bases. It is desirable because of its good castability and machinability, damping characteristics, and high performance-to-cost ratio. On the other hand, weak graphite flakes present in gray cast iron serve as stress concentrators and adversely affect the material strength. Therefore, it is crucial to examine the relationship between the distribution of graphite flakes and the strength or fracture of gray cast iron. In this study, tensile tests on gray cast iron were carried out using a plate specimen and observed by scanning electron microscopy, and the microscopic deformation was observed on the specimen surface. Particularly, the change in the size of graphite flakes during the tensile tests was examined, and the observed trend was discussed. The experimental results reveal that the dimensional changes in the graphite flakes vary in the observed area and that the final fracture occurs in an area where a large dimensional change is observed, suggesting that the fracture location or critical parts of gray cast iron can be predicted from the dimensional changes of the graphite flakes at an early stage of deformation.
en-copyright=
kn-copyright=

en-aut-name=TadaNaoya
en-aut-sei=Tada
en-aut-mei=Naoya
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=UemoriTakeshi
en-aut-sei=Uemori
en-aut-mei=Takeshi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=SakamotoJunji
en-aut-sei=Sakamoto
en-aut-mei=Junji
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

affil-num=1
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=2
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=3
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=
END

start-ver=1.4
cd-journal=joma
no-vol=10
cd-vols=
no-issue=14
article-no=
start-page=4883
end-page=
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2020
dt-pub=20200716
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Finite Element Study of the Effect of Internal Cracks on Surface Profile Change due to Low Loading of Turbine Blade
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Turbine blades for thermal power plants are exposed to severe environments, making it necessary to ensure safety against damage, such as crack formation. A previous method detected internal cracks by applying a small load to a target member. Changes in the surface properties of the material were detected before and after the load using a digital holographic microscope and a digital height correlation method. In this study, this technique was applied in combination with finite element analysis using a 2D and 3D model simulating the turbine blades. Analysis clarified that the change in the surface properties under a small load varied according to the presence or absence of a crack, and elucidated the strain distribution that caused the difference in the change. In addition, analyses of the 2D model considering the material anisotropy and thermal barrier coating were conducted. The difference in the change in the surface properties and strain distribution according to the presence or absence of cracks was elucidated. The difference in the change in the top surface height distribution of the materials with and without a crack was directly proportional to the crack length. As the value was large with respect to the vertical resolution of 0.2 nm of the digital holographic microscope, the change could be detected by the microscope.
en-copyright=
kn-copyright=

en-aut-name=SakamotoJunji
en-aut-sei=Sakamoto
en-aut-mei=Junji
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=TadaNaoya
en-aut-sei=Tada
en-aut-mei=Naoya
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=UemoriTakeshi
en-aut-sei=Uemori
en-aut-mei=Takeshi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=KuniyasuHayato
en-aut-sei=Kuniyasu
en-aut-mei=Hayato
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

affil-num=1
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=2
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=3
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=4
en-affil=Shimadzu Corporation
kn-affil=
en-keyword=nondestructive inspection
kn-keyword=nondestructive inspection
en-keyword=crack detection
kn-keyword=crack detection
en-keyword=low loading
kn-keyword=low loading
en-keyword=surface profile
kn-keyword=surface profile
en-keyword=turbine blade
kn-keyword=turbine blade
en-keyword=finite element analysis
kn-keyword=finite element analysis
END

start-ver=1.4
cd-journal=joma
no-vol=9
cd-vols=
no-issue=7
article-no=
start-page=783
end-page=
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2019
dt-pub=20190712
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Effect of Lubrication and Forging Load on Surface Roughness, Residual Stress, and Deformation of Cold Forging Tools
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Cold forging is a metal forming that which uses localized compressive force at room temperature. During the cold forging process, the tool is subjected to extremely high loads and abrasive wear. Lubrication plays an important role in cold forging to improve product quality and tool life by preventing direct metallic contact. Surface roughness and residual stress also greatly affects the service life of a tool. In this study, variations in surface roughness, residual stress, and specimen deformation with the number of cold forging cycles were investigated under different forging conditions. Specimens that were made of heat-treated SKH51 (59-61 HRC), a high-speed tool steel with a polished working surface, were used. The specimens were subjected to an upsetting process. Compressive residual stress, surface roughness, and specimen deformation showed a positive relationship with the number of forging cycles up to a certain limit and became almost constant in most of the forging conditions. A larger change in residual stress and surface roughness was observed at the center of the specimens in all the forging conditions. The effect of the magnitude of the forging load on the above discussed parameters is large when compared to the effect of the lubrication conditions.
en-copyright=
kn-copyright=

en-aut-name=KarunathilakaNuwan
en-aut-sei=Karunathilaka
en-aut-mei=Nuwan
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=TadaNaoya
en-aut-sei=Tada
en-aut-mei=Naoya
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=UemoriTakeshi
en-aut-sei=Uemori
en-aut-mei=Takeshi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=HanamitsuRyota
en-aut-sei=Hanamitsu
en-aut-mei=Ryota
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

en-aut-name=FujiiMasahiro
en-aut-sei=Fujii
en-aut-mei=Masahiro
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=5
ORCID=

en-aut-name=OmiyaYuya
en-aut-sei=Omiya
en-aut-mei=Yuya
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=6
ORCID=

en-aut-name=KawanoMasahiro
en-aut-sei=Kawano
en-aut-mei=Masahiro
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=7
ORCID=

affil-num=1
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=2
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=3
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=4
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=5
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=6
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=7
en-affil=Zeno Tech Co., Ltd
kn-affil=
en-keyword=cold forging
kn-keyword=cold forging
en-keyword=high-speed tool steel
kn-keyword=high-speed tool steel
en-keyword=lubrication
kn-keyword=lubrication
en-keyword=residual stress
kn-keyword=residual stress
en-keyword=surface roughness
kn-keyword=surface roughness
en-keyword=tool deformation
kn-keyword=tool deformation
END

start-ver=1.4
cd-journal=joma
no-vol=36
cd-vols=
no-issue=1
article-no=
start-page=7
end-page=16
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2001
dt-pub=200112
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Microscopic Observation of Tensile Deformation Behavior of Polycrystalline Titanium with Scanning Probe Microscope
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=The change in the surface morphology of polycrystalline titanium during tensile plastic deformation is studied, using the scanning probe microscope as well as the laser scanning microscope. The observation shows that the slip occurs mainly near grain boundary at the strain range of ƒÃ < 0.05. The slip develops with the applied strain, and the slip on the second slip system or the crossing of slip lines appear. The surface roughness increases linearly with the applied strain. The height difference between the
grain boundary area and the inner grain area also increases with the applied strain, though the increase rate becomes low after the applied strain of about 0.3. The nano-scale height difference of the surface step of slip lines increases with the applied strain, though it remains almost constant after the applied strain of 0.4. The averaged surface roughness measured with the scanning probe microscope is in good agreement with that measured with the laser scanning microscope.
en-copyright=
kn-copyright=

en-aut-name=LiYan
en-aut-sei=Li
en-aut-mei=Yan
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=AbeTakeji
en-aut-sei=Abe
en-aut-mei=Takeji
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=TadaNaoya
en-aut-sei=Tada
en-aut-mei=Naoya
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=KanazawaMasanori
en-aut-sei=Kanazawa
en-aut-mei=Masanori
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

affil-num=1
en-affil=
kn-affil=Graduate School of Natural Science and Technology Okayama University

affil-num=2
en-affil=
kn-affil=Graduate School of Natural Science and Technology Okayama University

affil-num=3
en-affil=
kn-affil=Graduate School of Natural Science and Technology Okayama University

affil-num=4
en-affil=
kn-affil=Graduate School of Natural Science and Technology Okayama University
en-keyword=Plasticity
kn-keyword=Plasticity
en-keyword=Polycrystalline Titanium
kn-keyword=Polycrystalline Titanium
en-keyword=Tensile Deformation
kn-keyword=Tensile Deformation
en-keyword=Surface Morphology
kn-keyword=Surface Morphology
en-keyword=Slip
kn-keyword=Slip
en-keyword=Twin
kn-keyword=Twin
en-keyword=Probe Scanning Microscope
kn-keyword=Probe Scanning Microscope
en-keyword=Laser Scanning Microscope
kn-keyword=Laser Scanning Microscope
END

start-ver=1.4
cd-journal=joma
no-vol=36
cd-vols=
no-issue=1
article-no=
start-page=1
end-page=6
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2001
dt-pub=200112
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Observation of Orientation Change During Plastic Deformation of Polycrystalline Copper by EBSD Method
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Change in crystal orientation and strain of individual grains during tensile plastic deformation are studied to clarify on the microscopic deformation behavior of polycrystalline copper. The orientation of grain is measured by electron backscatter diffraction (EBSD) technique in the scanning electron microscope. The principal strain of grain is also measured by obtaining the approximated ellipse of strain distribution. The deformation of grains dependent on their initial orientation and the rotation of the principal strain during uniaxial tension are clarified.
en-copyright=
kn-copyright=

en-aut-name=KondouRyouji
en-aut-sei=Kondou
en-aut-mei=Ryouji
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=AbeTakeji
en-aut-sei=Abe
en-aut-mei=Takeji
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=TadaNaoya
en-aut-sei=Tada
en-aut-mei=Naoya
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=ShimizuIchiro
en-aut-sei=Shimizu
en-aut-mei=Ichiro
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

affil-num=1
en-affil=
kn-affil=Graduate School of Natural Science and Technology Okayama University

affil-num=2
en-affil=
kn-affil=Graduate School of Natural Science and Technology Okayama University

affil-num=3
en-affil=
kn-affil=Graduate School of Natural Science and Technology Okayama University

affil-num=4
en-affil=
kn-affil=Graduate School of Natural Science and Technology Okayama University
en-keyword=Polycrystalline Copper
kn-keyword=Polycrystalline Copper
en-keyword=Plastic Deformation
kn-keyword=Plastic Deformation
en-keyword=SEM
kn-keyword=SEM
en-keyword=EBSD Method
kn-keyword=EBSD Method
en-keyword=Grain Orientation
kn-keyword=Grain Orientation
en-keyword=Crystal Orientation Map
kn-keyword=Crystal Orientation Map
END

start-ver=1.4
cd-journal=joma
no-vol=39
cd-vols=
no-issue=1
article-no=
start-page=7
end-page=15
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2005
dt-pub=200501
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Microscopic Surface Change of Polycrystalline Aluminum duringTensile Plastic Deformation
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Roughening on free surface of polycrystalline metal during plastic deformation is closely related to the
inhomogeneous deformation in the respective grain at the surface. Uniaxial tensile tests are carried out on
annealed pure aluminum sheet specimens with various averaged grain sizes. The roughening is measured by
a 3-dimensional stylus instrument to examine the roughness change in both sides of specimen surfaces at each strain. The irregularities on one side are reversed on the backside, when the averaged grain size is as large as the thickness of the specimen. Discussions are made on the relation between the surface shapes of both sides adopting the cross correlation factor. The strains of respective grains are also measured from the grain boundary shape before and after plastic deformation. There are some deviations in the strains of the grains and their standard deviation increases with the applied strain.
en-copyright=
kn-copyright=

en-aut-name=WangXiaoqun
en-aut-sei=Wang
en-aut-mei=Xiaoqun
kn-aut-name=‰¤‹ÅŒQ
kn-aut-sei=‰¤
kn-aut-mei=‹ÅŒQ
aut-affil-num=1
ORCID=

en-aut-name=AbeTakeji
en-aut-sei=Abe
en-aut-mei=Takeji
kn-aut-name=ˆ¢•”•�Ž¡
kn-aut-sei=ˆ¢•”
kn-aut-mei=•�Ž¡
aut-affil-num=2
ORCID=

en-aut-name=TadaNaoya
en-aut-sei=Tada
en-aut-mei=Naoya
kn-aut-name=‘½“c’¼�Æ
kn-aut-sei=‘½“c
kn-aut-mei=’¼�Æ
aut-affil-num=3
ORCID=

en-aut-name=ShimizuIchiro
en-aut-sei=Shimizu
en-aut-mei=Ichiro
kn-aut-name=�´�…ˆê˜Y
kn-aut-sei=�´�…
kn-aut-mei=ˆê˜Y
aut-affil-num=4
ORCID=

affil-num=1
en-affil=
kn-affil=Graduate School of Natural Science and Technology Okayama University

affil-num=2
en-affil=
kn-affil=Tsuyama College of Technology

affil-num=3
en-affil=
kn-affil=Dept. of Mechanical Engineering Okayama University

affil-num=4
en-affil=
kn-affil=Dept. of Mechanical Engineering Okayama University
END