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Affiliation |
Faculty of Environment and Information Sciences, Division of Artificial Environment and Information |
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Job Title |
Assistant Professor |
YAHAGI Tsukaho
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Degree 【 display / non-display 】
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Doctor of Engineering - Yokohama National University
Campus Career 【 display / non-display 】
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2024.4
Duty Yokohama National UniversityFaculty of Environment and Information Sciences Division of Artificial Environment and Information Assistant Professor
Books 【 display / non-display 】
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すぐ身につく分析化学・機器分析の実務 : 基礎、前処理、手法選択、記録作成を現場目線で解説
矢矧 束穂, 瀬戸山 央（ Role： Sole author）
日刊工業新聞社 （ ISBN:9784526080456 ）
Language：Japanese Book type：Scholarly book
Papers 【 display / non-display 】
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Yahagi, T; Ohji, T; Yamaguchi, H; Takahashi, T; Nakano, H; Iijima, M; Tatami, J
ADVANCED ENGINEERING MATERIALS 26 ( 18 ) 2024.9
Language：Japanese Publishing type：Research paper (scientific journal) Joint Work
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Microscopic mechanical properties of silicon nitride ceramics corroded in sulfuric acid solution
Tatami, J; Uda, M; Takahashi, T; Yahagi, T; Iijima, M; Matsui, K; Ohji, T; Nakano, H
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY 44 ( 9 ) 5415 - 5421 2024.8
Language：Japanese Publishing type：Research paper (scientific journal) Joint Work
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Micro-scale mechanical properties of surface layer in ion-exchanged glass
Fujita Saho, Ohji Tatsuki, Yahagi Tsukaho, Iijima Motoyuki, Tatami Junichi
Journal of the American Ceramic Society 107 ( 6 ) 3666 - 3672 2024.2
Language：English Publishing type：Research paper (scientific journal) Publisher：The American Ceramic Society Joint Work
Today, ion-exchanged or chemically strengthened glass is ubiquitously used all over the world, typically for scratch-free display cover of personal mobile phones. It has been known that the strengthening is due to developments of high compressive stress in the surface layer by its internally constrained dilation . We investigated micro-scale mechanical properties of the surface layer itself of a Na+-to-K+ ion-exchanged soda lime silicate glass, revealing that the strength of the layer increased nearly 40% by the ion-exchange with little compression effect from the interior. The fracture toughness, however, was comparable before and after the ion-exchange, indicating that the ion-exchange reduces the crack size of the fracture origin. Theoretical estimates of fracture surface energies verified the measured fracture toughness. It was presumed that the observed crack-size reduction is due to crack healing effects enhanced by the ion-exchange.
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Muramoto, M; Tatami, J; Iijima, M; Matsui, K; Yahagi, T; Takahashi, T; Nakano, H; Ohji, T
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY 44 ( 2 ) 1061 - 1069 2024.2
Language：Japanese Publishing type：Research paper (scientific journal) Joint Work
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Muramoto Mayuko, Tatami Junichi, Iijima Motoyuki, Matsui Kazumi, Yahagi Tsukaho, Takahashi Takuma, … Show more authors
Muramoto Mayuko, Tatami Junichi, Iijima Motoyuki, Matsui Kazumi, Yahagi Tsukaho, Takahashi Takuma, Nakano Hiromi, Ohji Tatsuki Hide authors
Journal of the European Ceramic Society 44 ( 2 ) 1061 - 1069 2023.11
Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier Science Ltd. Joint Work
Yield phenomena and bending strength of single crystal 8YSZ were evaluated using microcantilever beam specimens with various crystal orientations. Nonlinearity due to plastic deformation was observed in the stress strain curves, and the yield stress was found to depend on the crystal orientation. TEM observation revealed many areas of disordered lattice in the region where the maximum tensile stress occurred. Resolved shear stress (RSS) was analyzed for the primary {001} and the secondary {110} and {111} slip systems as a function of the angle between the specimen's longitudinal direction and the [001] orientation, indicating that the RSS for the secondary ones was the critical RSS in the angle at 10 degrees or lower while that for the primary one did so at 20 degrees or higher. The measured bending strength, which depended on the crystal orientation, was lower than, but on the same order of magnitude as, the ideal strength.