朱银波副教授 [中国科学技术大学]

Title: Microstructure topology and phase transition of amorphous carbon

Language:  Chinese presentation with English slides

Time: 15:00 - 16:00 PM, Wednesday March 27, 2024

Place: Onsite：Conference room A417, HPSTAR (Beijing)            Online: Tencent Meeting: https://meeting.tencent.com/dm/wDYZx5HkVzH5  Meeting ID: 396-266-316

Host:  Dr. Huiyang Gou

Abstract:

It is of the utmost importance to extend the models and methods of multiscale mechanics that would provide in-depth understanding for the structure-property-function relationships of materials. The combination of different building blocks into complex architectures has opened unprecedented opportunities in materials science and engineering. We focus on the multi-scale structure-property relationships and design in hierarchical materials and the intrinsic correlation between the mechanical behavior and application functions of advanced materials to achieve application-oriented mechanical design of hierarchical microstructures and interfaces of advanced materials. Based on large-scale molecular dynamics simulations and meta-dynamics simulations, we have discovered reversible continuous phase transitions of different steady state/substable structures, elucidated the temperature effect of paracrystalline diamond(p-D) nucleation, and revealed why p-D phases exist in high-density amorphous carbon and how to form stable hypocrystalline structures. The discontinuous phase diagrams of amorphous carbon are further given, and a variety of structural phase transitions between different types of amorphous carbon synergistically regulated by pressure/temperature are found. Starting from the structure of disordered three-dimensional graphene networks with different densities, the mechanisms of high-temperature and high-pressure-induced bond-breaking, bond-forming, and typical dislocation forms in the initial structure on the nucleation growth of nano diamonds in a-DG during the phase transition process have been elucidated, and it is summarized that there exists a variety of typical co-lattice/non-congruent interfacial atomic structures in a-DG. The related findings are expected to provide new perspectives for the mechanical study and large-size preparation of amorphous carbon materials.

扩展多尺度力学的模型和方法对于深入理解材料的结构-性能-功能关系具有重要意义。将不同的构建模块组合成复杂的架构，为材料科学和工程带来了前所未有的机遇。我们聚焦于分层材料中多尺度结构-性能关系和设计，以及先进材料的机械行为和应用功能之间的内在相关性，实现面向应用需求的先进材料层次化微结构和界面的力学设计。我们基于大规模分子动力学模拟和元动力学模拟，发现了不同稳态/亚稳态结构的可逆连续相变，阐明了次晶金刚石p-D成核生长的温度效应，揭示了高密度无定形碳为什么存在p-D相态以及如何形成稳定的次晶结构。进一步给出了无定形碳的非连续相图，发现多种受压强/温度协同调控的不同类型无定形碳之间的结构相变。从不同密度的无序三维石墨烯网络结构出发，阐明了相变过程中高温高压诱导断键、成键及初始结构中典型位错形式对a-DG中的纳米金刚石形核生长的作用机制，归纳了a-DG中存在多种典型的共格/非共格界面原子结构。相关研究结果有望为无定形碳材料的力学研究和大尺寸制备提供新的视角。

Biography of the Speaker:

Yinbo Zhu

Associate professor

Department of Modern Mechanics, University of Science and Technology of China

Email: zhuyinbo@mail.ustc.edu.cn 

Education and working Experience

2017年在中国科学技术大学获得固体力学博士学位。

2017.06-2019.05, 中国科学技术大学，博士后

2019.06-2021.12, 中国科学技术大学，聘期制副研究员

2022.01至今，中国科学技术大学，近代力学系，副教授

2017年6月获得中国科学技术大学固体力学博士学位（导师：吴恒安教授），同年获得中国科学院院长特别奖。 入选2017年度博士后创新人才支持计划，

2022年度中国科学院青年创新促进会；

曾获得2017年度中国科学技术大学优秀博士学位论文奖，2018年度中国科学院优秀博士学位论文奖，2019年度中国科学院特别研究助理资助。