一、 讲座题目

有序无序结构纠缠和超临界弹性—大科学装置在先进材料研发中的应用

二、 主讲人

任洋（香港城市大学物理学系教授）

三、 主讲内容

1822年，法国工程师/物理学家发现了超临界流体状态。1689年，一位爱尔兰化学家/物理学家报告了他在液—气系统方面的工作，发现在临界点以上，气体和液体可以连续地相互转化，而不需要经过不连续的气—液相变。继这些早期工作之后，现代统计热力学得到了很好的发展。然而，超临界状态的性质仍在争论中。一个原因可能是由于液体的原子结构很复杂。在这里，我们表明形状记忆合金(SMA) 的马氏体转变也表现出临界行为，这可能导致超过15%的无滞后超临界弹性(SCE)和1.6GPa的断裂强度。这种应力诱导马氏体相变(SIMT)类似于气液系统等温压力-体积曲线的特征。通过利用同步加速器 X 射线和中子设备以及电子显微镜技术，我们发现SCE与前所未有的微观结构密切相关，该微观结构由有序/无序晶体结构的原子级纠缠组成。与纠缠结构相关的大弹性的发现不仅为弹性应变工程的开发和相关功能材料的开发铺平了道路，而且有助于从原子尺度结构方面揭示超临界状态的本质。

四、 报告时间

2022年12月1日（星期四）下午2:30-4:00

五、主讲人简介

Dr. REN is a Chair Professor at Department of Physics, and Associate Dean (Internationalization) of College of Science, City University of Hong Kong (CityU). Prior to joining CityU in 2021, he was a Senior Physicist at Argonne National Laboratory, and a lead beamline scientist at Advanced Photon Source. He was awarded Hong Kong Global STEM Professorship (2021), and Argonne National Laboratory Board of Governors’ Distinguished Performance Award (2020) and Gopal K. Shenoy Excellence in Beamline Science Award, Advanced Photon Source (2020). He received his M.S. in condensed matter physics from the Institute of Physics, Chinese Academy of Science, and his Ph.D. in chemical physics from the University of Groningen, The Netherlands. His research interests focus on the structure-property studies of materials by utilizing synchrotron X-ray and neutron scattering and other techniques. His research activities include the investigation of phase transition, correlated electron systems, engineering materials, nanoparticles and nanocomposites, energy storage and conversion materials. He has published nearly 900 peer reviewed articles in Nature, Science, PRL and other prestigious journals. He is Clarivate’s High Cited Researcher (2022). He has Google H-index of 101 with citations over 38,000.

六、主持人

张俊杰（晶体材料国家重点实验室，教授）

七、参会方式

线上直播