Observation of a metastable intermediate during solid-solid phase transformation in response to rapid compression
Michael R. Armstrong, Harry B. Radousky, Ryan A. Austin, Elissaios Stavrou, Hongxiang Zong, Graeme J. Ackland, Shaughnessy Brown, Jonathan C. Crowhurst, Arianna… 展开作者
Michael R. Armstrong, Harry B. Radousky, Ryan A. Austin, Elissaios Stavrou, Hongxiang Zong, Graeme J. Ackland, Shaughnessy Brown, Jonathan C. Crowhurst, Arianna E. Gleason, Eduardo Granados, Paulius Grivickas, Nicholas Holtgrewe, Hae Ja Lee, Tian T. Li, Sergey Lobanov, Joseph T. McKeown, Robert Nagler, Inhyuk Nam, Art J. Nelson, Vitali Prakapenka, Clemens Prescher, John D. Roehling, Nick E. Teslich, Peter Walter, Alexander F. Goncharov, Jonathan L. Belof
In order to probe the mechanism of solid-solid phase transformations, we have applied ultrafast shock wave compression (120 picosecond duration) and ultrashort (130 femtosecond) x-ray diffraction at the Linac Coherent Light Source (LCLS) to probe the compression-induced phase transition pathway in zirconium. Surprisingly, rather than transform from alpha-Zr to the more disordered hex-3 equilibrium omega-Zr phase, in its place we find the formation of a non-equilibrium body-centered cubic (bcc) metastable intermediate. Theoretically hypothesized for several decades, this bcc intermediate state has now been found to be dynamically stabilized under uniaxial loading at sub-nanosecond timescales. Molecular dynamics simulations of shock-wave propagation in zirconium predict this transformation via the dynamical intermediate state. In contrast with longer timescale experiments where the phase diagram alone is an adequate predictor of the crystalline structure of a material, our recent study highlights the importance of metastability and time-dependence in the kinetics of phase transformation at extreme conditions.
Leveraging rapid sintering to retain metastable zirconia in copper
Nanyang Technological University（南洋理工大学）；Shanghai Jiao Tong University（上海交通大学）；Singapore Centre for 3D Printing, Nanyang Technological University（南洋理工大学三维打印中心）；Department of Civil Engineering, TongJi ZheJiang College（同济大学浙江学院土木工程系）
Time-Temperature-Transformation (TTT) Diagrams to rationalize the nucleation and quenchability of metastable $α$-Li$_3$PS$_4$
Faculty of Engineering, Hokkaido University（北海道大学工学部）；Department of Materials Science and Engineering, University of Michigan（密歇根大学材料科学与工程系）；Department of Physics, Tokyo Metropolitan University（东京都立大学物理学系）；Graduate School of Advanced Science and Engineering, Hiroshima University（广岛大学先进理工学研究科）；Japan Synchrotron Radiation Research Institute（日本同步辐射研究所）；Department of Materials Science, Graduate School of Engineering, Osaka Metropolitan University（大阪公立大学工学研究科材料科学系）；Department of Applied Chemistry, Graduate School of Engineering, Osaka Metropolitan University（大阪公立大学工学研究科应用化学系）；Institute for Materials Research, Tohoku University（东北大学物质研究所）
Microstructural and Mechanistic Insights into the Tension-Compression Asymmetry of Rapidly Solidified Fe-Cr Alloys: A Phase Field and Strain Gradient Plasticity Study
Thermally quenched metastability in metal-insulator transitions via elemental substitution
The University of Tokyo（东京大学）；National Institute of Advanced Industrial Science and Technology（产业技术综合研究所）；Graduate School of Engineering and Science, Shibaura Institute of Technology（芝浦工业大学研究生院理工学研究科）；RIKEN Center for Emergent Matter Science（理化学研究所新兴物质科学研究中心）；University of Tsukuba（筑波大学）；Institute of Science Tokyo（东京科学大学）；National Institute for Materials Science（国立材料研究所）
Cornell University（康奈尔大学）；University of Bern（伯尔尼大学）；California Institute of Technology（加州理工学院）
人工智能（AI）实现的自主实验为加速科学发现提供了新的范式。非平衡材料合成是复杂的资源密集型实验的象征，其加速将成为材料发现和开发的分水岭。非平衡合成相图的绘制最近已经通过高通量实验加速，但仍然限制了材料研究，因为参数空间太大而无法穷尽地探索。我们展示了加速合成和探索的亚稳态材料，通过分层自治实验的科学自主推理代理（SARA）。SARA集成了机器人材料合成和表征以及AI方法的层次结构，有效地揭示了加工相图的结构。SARA设计了用于平行材料合成的横向梯度激光尖峰退火（lg-LSA）实验，并采用光学光谱法快速识别相变。多维参数空间的有效探索是通过建立在先进机器学习模型基础上的嵌套主动学习（AL）循环实现的，该模型结合了实验的基础物理学以及端到端的不确定性量化。有了这一点，以及人工智能在多个尺度上的协调，SARA体现了人工智能对复杂科学任务的利用。我们证明了其性能，通过自主映射合成相边界的Bi $_2$ O $_3$系统，导致订单的数量级加速建立的合成相图，其中包括动力学稳定的条件$δ$-Bi $_2$ O $_3$在室温下，一个关键的发展，如固体氧化物燃料电池的电化学技术。
