Materials Development Division

Structure-Controlled Functional Materials Research Laboratory

Tetsu ICHITSUBO

Prof.Tetsu ICHITSUBO

  • Assoc. Prof. Norihiko OKAMOTO
  • Assist. Prof. Hiroshi TANIMURA
  • Assist. Prof. Tomoya KAWAGUCHI

Development of Novel Functional/Structural Materials Through Structural Control or Phase-Transformation Process

Since 2018, our laboratory name has been changed to "Structure-Controlled Functional Materials". In our laboratory, we aim to develop novel materials exhibiting new functions (in terms of mechanical properties, electrical, optical properties, etc) by controlling the material structures, with the aid of several experimental techniques such as high-frequency internal friction measurement, synchrotron X-ray/electron-beam diffraction analysis, femtosecond laser pump-probe measurement, and so on. Our study field is mainly based on the materials microstructure theory, thermal statistical thermodynamics, micromechanics theory, and electrochemistry.

Specifically, we focus on: (i) microstructure formation dynamics of solid-solid phase phase transition and its control by application of external fields, (ii) elucidation of relaxation mechanism and structural inhomogeneity in metallic glasses and their analog high-entropy alloys using megahertz oscillation and internal friction techniques, (iii) energy materials for novel energy storage systems and thermoelectric materials, (iv) ultrafast photoinduced phase change materials, and (v) material design utilizing phase transition such as titanium alloys, etc. In the end, we aim to investigate across the various fields to develop new materials possessing new functionalities.

phase transition dynamics, electrode microstructure study, amorphous material, micromechanics
The partially crystallized structureunder ultrasonic oscillation resonating withβ relaxation of a Pd-based metallic glass

(Left) Scanning transmission electron microscope image of nm-sized diffusionless isothermalω phase in β-type titanium alloys (Ti-V). The inset shows the temperature dependence of the internal friction corresponding to the elementary process of βω transformation, indicating that the low-temperature aging induces diffusionless isothermal ω transformation in the β unstable region as well as that a small amount of Sn addition reduces the β unstable region and suppresses ω transformation.

(Right) Charge/discharge process of disordered rocksalt oxide cathodes for rechargeable magnesium batteries. Li extraction in the initial charging creates cation vacancies (upper left ⇔ upper right). Mg is reversibly inserted and extracted in the subsequent charge/discharge cycles via the created vacancies (upper right ⇔ lower right). Controlling the lowest average valence of constituent elements preserves the vacancies after Mg insertion and ensures electrode reversibility (bottom left).

About IMR