Updated on 2024/07/14

写真a

 
TAKAMATSU, Satomi
 
Affiliation
Faculty of Science and Engineering, Graduate School of Fundamental Science and Engineering
Job title
Assistant Professor(without tenure)

Research Experience

  • 2024.04
    -
    Now

    Waseda University   Assistant professor

 

Papers

  • Percolation of primary crystals in cell walls of aluminum alloy foam via semi-solid route

    Satomi Takamatsu, Takashi Kuwahara, Ryunosuke Kochi, Shinsuke Suzuki

    Metals   10 ( 7 ) 1 - 13  2020.07

     View Summary

    Herein, a uniform aluminum alloy foam was fabricated by the addition of TiH2 as a blowing agent to Al-6.4 mass % Si in the semi-solid state and subsequent solidification. This was aimed at propounding the stabilization mechanism of the proposed foaming process. The microscopic images, which were the cross section on the center of the foam etched with Weck’s reagent, showed the primary crystals in the semi-solid state and solidifying segregation surrounding the crystals. Thus, it became evident that the area ratio of primary crystals in the semi-solid state approximately equals to the set solid fraction. According to the percolation theory for the cell wall model, the drainage in the cell walls with primary crystals above the percolation threshold was found to be inhibited. By considering that each cell wall is a flow path of the foam, the percentage of the cell walls with inhibited drainage to all the other cell walls was observed to exceed the percolation threshold of the lattice model (0.33) as per the percolation theory. Therefore, it can be concluded that the primary crystals inhibit drainage in some cell walls, ensuring that the stability of the foam is maintained.

    DOI

    Scopus

    4
    Citation
    (Scopus)
  • Stabilization mechanism of semi-solid film simulating the cell wall during fabrication of aluminum foam

    Takashi Kuwahara, Akira Kaya, Taro Osaka, Satomi Takamatsu, Shinsuke Suzuki

    Metals   10 ( 3 )  2020.03

     View Summary

    Semi-solid route is a fabrication method of aluminum foam where the melt is thickened by primary crystals. In this study, semi-solid aluminum alloy films were made to observe and evaluate the stabilization mechanism of cell walls in Semi-solid route. Each film was held at different solid fractions and holding times. In lower solid fractions, as the holding time increases, the remaining melt in the films lessens and this could be explained by Poiseuille flow. However, the decreasing tendency of the remaining melt in the films lessens as the solid fraction increases. Moreover, when the solid fraction is high, decreasing tendency was not observed. These are because at a certain moment, clogging of primary crystals occurs under the thinnest part of the film and drainage is largely suppressed. Moreover, clogging is occurring in solid fraction of 20–45% under the thinnest part of the film. Moreover, the time to occur clogging becomes earlier as the solid fraction increases.

    DOI

    Scopus

    6
    Citation
    (Scopus)