HIROSAWA Shoichi

Affiliation

Faculty of Engineering, Division of Systems Research

Job Title

Professor

Date of Birth

1969

Research Fields, Keywords

Structural Materials Design, Microstructural Control and Analysis, Computational Materials Science

Mail Address

E-mail address

Related SDGs




写真a

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The Best Research Achievement in the last 5 years 【 display / non-display 】

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Graduating School 【 display / non-display 】

  • 　
    -
    1993

    Tokyo Institute of Technology   Faculty of Engineering   Department of Metallurgical Engineering   Graduated

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Graduate School 【 display / non-display 】

  • 　
    -
    1998

    Tokyo Institute of Technology  Graduate School, Division of Science and Engineering  Department of Metallurgical Engineering  Doctor Course  Completed

  • 　
    -
    1995

    Tokyo Institute of Technology  Graduate School, Division of Science and Engineering  Department of Metallurgical Engineering  Master Course  Completed

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Degree 【 display / non-display 】

  • Doctor of Engineering -  Tokyo Institute of Technology

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Campus Career 【 display / non-display 】

  • 2017.04
    -
    Now

    Duty   Yokohama National UniversityFaculty of Engineering   Division of Systems Research   Professor  

  • 2014.04
    -
    2017.03

    Duty   Yokohama National UniversityFaculty of Engineering   Division of Materials Science and Chemical Engineering   Professor  

  • 2007.04
    -
    2014.03

    Duty   Yokohama National UniversityFaculty of Engineering   Division of Materials Science and Chemical Engineering   Associate Professor  

  • 2018.04
    -
    Now

    Concurrently   Yokohama National UniversityGraduate school of Engineering Science   Department of Mechanical Engineering, Materials Science and Ocean Engineering   Professor  

  • 2017.04
    -
    Now

    Concurrently   Yokohama National UniversityCollege of Engineering Science   Department of Mechanical Engineering, Materials Science and Ocean Engineering   Professor  

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External Career 【 display / non-display 】

  • 2002.01
    -
    2007.03

    Assistant Professor of Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology   Research Assistant  

  • 1999.04
    -
    2001.12

    University of Oxford   Research Associate of Department of Materials  

  • 1998.04
    -
    1999.02

    Technology and Medicine   Department of Materials, Imperial College of Science   Visiting Researcher  

  • 1997.04
    -
    1999.03

    Japan Society for the Promotion of Science   Research Fellowship for Young Scientists of the Japan Society for the Promotion of Science  

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Academic Society Affiliations 【 display / non-display 】

  • 2007
    　
    　
     

    Japan Society for Heat Treatment

  • 1997
    　
    　
     

    Japan Institute of Metals

  • 1993
    　
    　
     

    Japan Institute of Light Metals

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Field of expertise (Grants-in-aid for Scientific Research classification) 【 display / non-display 】

  • Structural/Functional materials

  • Physical properties of metals/Metal-base materials

  • Material processing/Microstructural control engineering

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Research Career 【 display / non-display 】

  • Development of age-hardening technology for ultrafine-grained aluminum alloys processed by severe plastic deformation

    Project Year：  -   

  • Development of new fabrication process of Al-Mg-Si alloy sheets for body-panels of automobiles

    Project Year：  -   

  • Development of novel heat-resistant aluminum alloys

    Project Year：  -   

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Books 【 display / non-display 】

  • Advanced Materials in Aerospace Engineering "Three strategies to achieve concurrent strengthening by ultrafine-grained and precipitation hardenings for severly deformed age-hardenable aluminum alloys"

    山根健ほか計34名 (Part： Contributor )

    Trans Tech Publications Inc.  2016.01

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Thesis for a degree 【 display / non-display 】

  • Microstructure Evolution and Role of Microalloying Elements in Phase Decomposition of Al-Li-Cu Base Alloys

    廣澤　渉一 

    Doctral thesis of Tokyo Institute of Technology    1998.03

    Doctoral Thesis   Single Work

    　View Summary

    東京工業大学理工学研究科金属工学専攻 種々のマイクロアロイング元素を含むAl-Li-Cu合金の析出組織形成を、TEM観察や電気比抵抗測定、熱分析およびモンテカルロシミュレーションを用いて明らかにし、原子間の相互作用エネルギーの大小で相分解挙動を分類・予測することで、より効率的な合金設計を可能とした

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Papers 【 display / non-display 】

  • Precipitate microstructures, mechanical properties and corrosion resistance of Al-1.0 wt%Cu-2.5 wt%Li alloys with different micro-alloyed elements addition

    D. Liu, Y. Ma, J. Li, R. Zhang, H. Iwaoka and S. Hirosawa

    Materials characterization ( Elsevier )  167   110528   2020.07  [Refereed]

    Joint Work

    　View Summary

    The evolution of precipitate microstructures of the Al-1.0wt%Cu-2.5wt%Li alloys with different micro-alloyed elements addition was investigated during ageing at 175 °C together with the mechanical properties and corrosion resistance. It was found that the Al-Cu-Li alloy with Zn addition possesses not only higher yield strength but also improved intergranular corrosion resistance, compared with the alloy with Mg addition. The corresponding precipitate microstructures were greatly affected by Zn or Mg micro-alloyed element addition, for example, with Zn addition the δ′-Al3Li, T1-Al2CuLi and θ′-Al2Cu (and θ″) phases were formed within grains, whereas the coarse TB-Al7Cu4Li phase and the T1 phases appeared at grain boundaries (GBs). In contrast, the Al-Cu-Li alloy with Mg addition possessed the δ′, T1 and S′-Al2CuMg phases within grains, while the coarse Alsingle bondCu phase and T1 phases were present at GBs. The alloy with combined Zn + Mg addition exhibited a duplex microstructure of the two alloys, resulting in lower mechanical strengths but the intermediate corrosion resistance. Therefore, the increased amount of Zn-containing coarsened TB phase at GBs was found to improve the corrosion resistance of the alloy with Zn addition, due to the smaller potential difference between the GB precipitates and the adjacent zones.

    DOI

  • Achieving highly strengthened Al–Cu–Mg alloy by grain refinement and grain boundary segregation

    T. Masuda, X. Sauvage, S. Hirosawa and Z. Horita

    Materials Science and engineering A ( Elsevier )  793   139668   2020.07  [Refereed]

    Joint Work

    　View Summary

    An age-hardenable Al–Cu–Mg alloy (A2024) was processed by high-pressure torsion (HPT) for producing an ultrafine-grained structure. The alloy was further aged for extra strengthening. The tensile strength then reached a value as high as ~1 GPa. The microstructures were analyzed by transmission electron microscopy and atom probe tomography. The mechanism for the high strength was clarified in terms of solid-solution hardening, cluster hardening, work hardening, dispersion hardening and grain boundary hardening. It is shown that the segregation of solute atoms at grain boundaries including subgrain boundaries plays a significant role for the enhancement of the tensile strength.

    DOI

  • Development of thermally stable powder metallurgy Al–Mn alloy extrusions and prediction of their terminal strength after prolonged service periods at high temperatures

    N. Maki, H. Iwaoka and S. Hirosawa

    Materials Science and Engineering: A ( Elsevier )  793   139813   2020.06  [Refereed]

    Joint Work

    　View Summary

    The demand for thermally stable aluminum alloys is increasing, but mechanical strength of most of existing alloys inevitably decreases when exposed to high temperature environments. In this study, newly developed powder metallurgy (P/M) Al–Mn alloy extrusions were subjected to full annealing treatment and temperature-accelerated test, to simulate decrease in hardness after prolonged service periods at high temperatures, and were found to possess higher thermal stability than a conventional ingot metallurgy (I/M) 3000 series Al–Mn alloy extrusion. Such improvement of high temperature strength was attributed to the increased volume fractions of thermally stable Al6Mn phase, and quantitatively explained according to the underlying strengthening mechanisms, by which their terminal strength after prolonged and thus practically unmeasurable periods could be predicted. Prediction of the microstructures and the corresponding Vickers hardness was also achieved by combining phase-field simulation and classical micromechanics approach, confirming that the utilized simulation model could enable to predict the terminal strength of the developed P/M alloy extrusions.

    DOI

  • First-principles calculation of elastic properties of Cu-Zn intermetallic compounds for improving the stiffness of aluminum alloys

    H.Iwaoka, S.Hirosawa

    Computational Materials Science ( Elsevier )  174   109479   2019.12  [Refereed]

    Joint Work

    　View Summary

    In this study, we computed the elastic properties of Cu-Zn binary intermetallic compounds, CuZn, Cu5Zn8 and CuZn4, by first-principles calculation and discussed the capability of the improvement in stiffness of aluminum alloys by aging treatment. The disordered CuZn4 with random atom distribution was emulated for the first time by virtual crystal approximation (VCA) model and special quasirandom structure (SQS) model with symmetry-based projection (SBP) technique. From the present calculation results, it was found that Young’s modulus of polycrystalline aggregate of CuZn4 is almost comparable to the highest counterpart of Cu5Zn8 with lower elastic anisotropy, but the expected volume fraction of CuZn4 is much higher than that of Cu5Zn8 after aging treatment. According to the rule of mixtures for the aluminum matrix and differently oriented intermetallic compounds, therefore, CuZn4 was rationally recommended as the most suitable intermetallic compound for improving the stiffness of Al-Cu-Zn alloys.

    DOI

  • Microstructures and the Mechanical Properties of the Al–Li–Cu Alloy Strengthened by the Combined Use of Accumulative Roll Bonding and Aging

    Yongpeng Tang, Shoichi Hirosawa, Seiji Saikawa, Kenji Matsuda, Seungwon Lee, Zenji Horita, Dai … Show more authors

    Advanced Science ( Wiley Online Library )    2019.06

    Joint Work

    DOI

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Review Papers 【 display / non-display 】

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Academic Awards Received 【 display / non-display 】

  • Light Metals Paper Prize

    2010.11.13    

  • Light Metals Paper Prize

    2007.11    

  • Young Scientist Award of Japan Institute of Light Metals

    2003.11    

  • Japan Institute of Metals Young Scientist Medal

    2002.09    

  • Light Metals Paper Prize

    1996.11    

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Grant-in-Aid for Scientific Research 【 display / non-display 】

  • Grant-in-Aid for Scientific Research(C)

    Project Year： 2010.04  -  2013.03 

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Other external funds procured 【 display / non-display 】

  • Development of novel wrought aluminum alloys concurrently strengthened by ultrafine-grained and precipitation hardenings and establishment of guidelines for the innovative alloy designing

    Offer organization: Japan Science and Technology Agency  Collaborative Research Based on Industrial Demand "Heterogeneous Structure Control: Towards Innovative Development of Metallic Structural Materials"

    Project Year： 2011.10  -  2017.03  Investigator(s): Shoichi HIROSAWA

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Presentations 【 display / non-display 】

  • Concurrent strengthening of ultrafine-grained age-hardenable Al-Mg alloy by means of high-pressure torsion and spinodal decomposition

     [Invited]

    2017.07.11  

  • Three strategies to achieve concurrent strengthening by ultrafine-grained and precipitation hardenings for severely deformed age-hardenable aluminum alloys

    S.Hirosawa, Y.Tang, Z.Horita, S.Lee, K.Matsuda, D. Terada  [Invited]

    9th Pacific Rim Inte. Conf. on Advanced Materials and Processing (PRICM9) (Three strategies to achieve concurrent strengthening by ultrafine-grained and precipitation hardenings for severely deformed age-hardenable aluminum alloys)  2016.08.04   9th Pacific Rim Inte. Conf. on Advanced Materials and Processing (PRICM9)

  • Comparative and complementary characterization of precipitate microstructures in Al-Mg-Si(-Li) alloys by TEM, EDS and APT

    S.Hirosawa, Y.Koshino, M.Kozuka, Y.Aruga

    15th Inter. Conf. on Aluminum Alloys (ICAA15) (Comparative and complementary characterization of precipitate microstructures in Al-Mg-Si(-Li) alloys by TEM, EDS and APT)  2016.06.13   15th Inter. Conf. on Aluminum Alloys (ICAA15)

  • Comparative and complementary characterization of precipitate microstructures in Al-Mg-Si(-Li) alloys

    2016.03.01  

  • Three strategies to achieve concurrent strengthening by ultrafine-grained and precipitation hardenings for severely deformed age-hardenable aluminum alloys

    S. Hirosawa, Y. Tang, Z. Horita, S. Lee, K. Matsuda, D. Terada

    International Workshop of Giant Straining Process for Advanced Materials 2015 (GSAM2015)(Three strategies to achieve concurrent strengthening by ultrafine-grained and precipitation hardenings for severely deformed age-hardenable aluminum alloys)  (Fukuoka)  2015.09.05  

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Past of Collaboration and Commissioned Research 【 display / non-display 】

  • Japan Science and Technology Agency (JST) under Collaborative Research Based on Industrial Demand "Heterogeneous Structure Control: Towards Innovative Development of Metallic Structural Materials"

    Cooperative Research within Japan  

    Project Year： 2011.10  -  2017.03 

  • Development of age-hardening technology for ultrafine-grained aluminum alloys processed by giant straining

    Cooperative Research within Japan  

    Project Year： 2009.04  -  2011.03 

  • Studies on creep behavior of aluminum alloys

    Cooperative Research within Japan  

    Project Year： 2007.04  -  2010.03 

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