清华大学材料科学与工程研究院《材料科学论坛》学术报告

报告时间：2025年10月15日上午10:00-11:30

报告人：Dr. Shigenobu Ogata（The University of Osaka）

报告地点：清华大学逸夫技术科学楼B213陶瓷报告厅

邀请人：陈浩老师

报告题目：Atomistic modeling of hydrogen effects on Fe and Fe-C alloys

报告简介：

Hydrogen profoundly alters the deformation and fracture behavior of structural metals, yet its spatiotemporal evolution in solids remains difficult to probe directly. Atomistic simulation offers a powerful route to interrogate hydrogen transport and its interactions with defects at relevant length and time scales, provided interatomic interactions are described with sufficient fidelity. Here we employ recently developed artificial‑neural‑network (ANN) interatomic potentials for Fe–H and Fe–C–H systems, trained on density functional theory (DFT) datasets comprising energies, forces, and relaxed structures. These ANN potentials deliver near‑DFT accuracy while retaining the computational efficiency and transferability required for large‑scale simulations, enabling quantitative analysis in bcc Fe and Fe–C alloys. Using this framework, we clarify how hydrogen influences vacancy migration, dislocation nucleation and glide, and crack initiation and growth at grain boundaries and within grain interiors. We further delineate carbon’s role in mediating these hydrogen effects, including its impact on trapping behavior and defect kinetics. Together, these capabilities provide a coherent, quantitative picture of hydrogen‑assisted damage in Fe‑based alloys and establish a robust toolset for predictive simulations of environmentally assisted cracking.

报告人简介：

Dr. Shigenobu Ogata is a Full Professor in the Department of Mechanical Science and Bioengineering in the University of Osaka. He is also Research Affiliate of the Department of Nuclear Science and Engineering, Massachusetts Institute of Technology (MIT), USA. He received his Ph.D. degree in Mechanical Engineering from Osaka University in 1998. He was a visiting research scientist in the Department of Nuclear Science and Engineering at MIT(USA) 2001 - 2002. He is an editor of Progress in Materials Science (IF: 40). He and his group aim to develop reliable theoretical models and neural network models for describing various nonlinear multiscale and/or multiphysics phenomena that appear in solid materials, and then to design materials with novel functions and a deformation process controlled at an atomic level in a predictive manner. He developed many mature and widely accepted models for the strength and deformation of materials; Amorphous deformation, Strength of crystal, Dislocation and Diffusion driven deformation, Hydrogen embrittlement and so on. His awards more than 20 include: Lee Hsun Lecture Award of Institute of Metal Research, China (2014).