The University of Tokyo · 재료과학
이 교수의 연구실은 분자 동역학 시뮬레이션과 위상장 모델을 활용해 철과 같은 체심입방금속 금속의 핵형성, 고체화 메커니즘, 격자 결함 및 표면 거동을 원자적 수준에서 연구합니다. 특히 GPU 기반 초고성능 계산 환경를 활용해 백만 원자 이상의 대규모 시뮬레이션을 통해 이방성의 고체 핵 형성, 이질적 핵형성, 이중 경계 에너지의 온도 의존성 등 고전적 이론으로는 설명하기 어려운 현상을 규명하고 있습니다. 연구는 원자적 거동에서 시작해 미세구조 수준의 거시적 거동으로 이어지는 다스케일 다이내믹스를 중심으로 전개됩니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Can completely homogeneous nucleation occur? Large scale molecular dynamics simulations performed on a graphics-processing-unit rich supercomputer can shed light on this long-standing issue. Here, a billion-atom molecular dynamics simulation of homogeneous nucleation from an undercooled iron melt reveals that some satellite-like small grains surrounding previously formed large grains exist in the middle of the nucleation process, which are not distributed uniformly. At the same time, grains with
The phase transition between liquid and solid phases in body-centered cubic (bcc) metal nanoparticles of iron, chromium, molybdenum, and tungsten with size ranging from 2000 to 31,250 atoms was investigated using a molecular dynamics simulation. The nucleation from an undercooled liquid droplet was observed during cooling in all nanoparticles considered. It was found that a nucleus was generated near one side of the particle and solidification spread toward the other side the during nucleation p
The temperature dependences of the energy and structure of the symmetric tilt boundary of bcc and fcc iron were investigated by molecular dynamics simulation. A large energy cusp was observed at the bcc(112)‹110›Σ3 and fcc(111)‹110›Σ3 grain boundary plane, which is a twin boundary, whereas it was not observed at the bcc(111)‹110›Σ3 plane in spite of it having the lowest Σ-value. The grain boundary energy increased at the temperature close to the melting point except for the grain boundary planes
Thanks to the recent progress in high-performance computational environments, the range of applications of computational metallurgy is expanding rapidly. In this paper, cutting-edge simulations of solidification from atomic to microstructural levels performed on a graphics processing unit (GPU) architecture are introduced with a brief introduction to advances in computational studies on solidification. In particular, million-atom molecular dynamics simulations captured the spontaneous evolution
Homogeneous nucleation from an undercooled iron melt is investigated by the statistical sampling of million-atom molecular dynamics (MD) simulations performed on a graphics processing unit (GPU). Fifty independent instances of isothermal MD calculations with one million atoms in a quasi-two-dimensional cell over a nanosecond reveal that the nucleation rate and the incubation time of nucleation as functions of temperature have characteristic shapes with a nose at the critical temperature. This in
A novel phase-field model for electrochemical processes, in which cations were driven by an electrostatic potential coupled with a thermodynamic potential, was formulated from a variation of the Ginzburg–Landau free-energy functional. Using this model, an electrodeposition process of copper deposits from copper-sulfate solution was studied using a phase-field simulation. The dependence of the growth velocity of the electrode on the applied voltage was examined in a one-dimensional system. Then,
