The University of Osaka · 재료과학
Jun-Ping Du 교수의 연구실은 고온 구조재료, 특히 니켈기 다상 초합금의 원자적 거동을 전산 시뮬레이션과 실험 데이터를 융합하여 연구합니다. 주요 연구 방향은 EAM 잠재에너지 퍼텐셜의 개발을 바탕으로 한 비틀림 결함, 불량 결합, 불순소의 영향 등 미세구조적 특성의 기계적 거동 분석입니다. 특히 루테늄, 리튬, 레니움 등 합금 첨가원소의 미세구조적 기여와 기계적 성질 향상 메커니즘을 다룹니다. 고체상태에서의 원자 이동, 결함 거동, 화학 순서 형성 등 물질의 거동을 원자 수준에서 이해하는 데 초점을 맞추고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Based on experiments and first-principles calculations, a Ni–Al–Re system embedded atom method (EAM) potential is constructed for the γ(Ni)/γ'(Ni3Al) superalloy. The contribution of the inner elastic constants is considered in the fitting of Re with a hexagonal close-packed structure. Using this potential, point defects, planar defects and lattice misfit of γ(Ni) and γ'(Ni3Al) are investigated. The interaction between Re and the misfit dislocation of the γ(Ni)/γ'(Ni3Al) system is also calculated
The formation of local chemical order in medium-entropy alloys and high-entropy alloys (MEAs/HEAs) has been strongly suggested in recent experimental observations. Since chemical order can lead to changes in mechanical and functional properties, tailoring of chemical order is a promising approach for further improving those properties of MEAs and HEAs. However, details remain unclear regarding the atomic structure of the chemical order and the formation kinetics. Here, employing a large-scale Mo
Vacancy diffusion is fundamental to materials science. Hydrogen atoms bind strongly to vacancies and are often believed to retard vacancy diffusion. Here, we use a potential-of-mean-force method to study the diffusion of vacancies in Cu and Pd. We find H atoms, instead of dragging, enhance the diffusivity of vacancies due to a positive hydrogen Gibbs excess at the saddle-point: that is, the migration saddle attracts more H than the vacancy ground state, characterized by an activation excess Γ<su
Accelerated molecular dynamics reveals a mechanism transition and strong temperature dependence of dislocation nucleation from grain boundaries (GBs) in Cu. At stress levels up to $\ensuremath{\sim}90%$ of the ideal dislocation-nucleation stress, atomic shuffling at the $E$ structural unit in a GB acts as a precursor to dislocation nucleation, and eventually a single dislocation is nucleated. At very high stress levels near the ideal dislocation-nucleation stress, a multiple dislocation is colle
An Ni—Al—Co system embedded-atom-method potential is constructed for the γ(Ni)/γ'(Ni3Al) superalloy based on experiments and first-principles calculations. The stacking fault energies (SFEs) of the Ni(Co, Al) random solid solutions are calculated as a function of the concentrations of Co and Al. The calculated SFEs decrease with increasing concentrations of Co and Al, which is consistent with the experimental results. The embedding energy term in the present potential has an important influence
In Ni-based single crystal superalloys, ruthenium is sometimes introduced as one of the creep resistances through retarding the thermally-activated deformation processes, such as dislocation glide and climb. In the present study, an embedded-atom-method potential of Ni–Al–Ru system was constructed. Using the present potential, the effect of Ru on the lattice misfit between γ(Ni) and γ'(Ni3Al) phases was investigated. The results show that Ru doping decreases the lattice misfit, which is consiste
