物理学院“博约学术论坛”系列报告第18期

物理学院“博约学术论坛”系列报告第18期        (2012年第7期)
 

题  目：Structure and dynamical properties in glass formation in CuZr metallic alloys
报告人：李茂枝 教授
单  位：中国人民大学物理系
时  间：2012年5月11日(星期五)上午10:00
地  点：中心教学楼701 

摘  要：
Describing the structure of amorphous materials such as metallic glasses and understanding the glass formation have been longstanding challenges in materials science. Despite enormous efforts and progress that have been made during the past several decades, a rational glass transition mechanism of real alloy systems is still absent. In this talk, I will talk about a distinct medium-range arrangement motif and an icosahedral two-phase structure observed in ZrCu binary metallic glasses. We find that the glass structure is a heterogeneous mixture of interpenetrating 13-atom icosahedral clusters connected in a string-like fashion forming a solid-like backbone network within a liquid-like matrix. A significant self-aggregation effect of icosahedral short-range order (ISRO) in high temperature ZrCu liquids is also discovered, which is highly consistent with that observed in atomic models of corresponding glass system. It is found that the development of ISRO upon cooling is driving the system into dynamical arrest. Moreover, the aggregation of ISRO remarkably enhances this effect and provides a positive feedback for the development of ISRO in the system. Due to its intrinsic non-space-filling character, the self-aggregation of ISRO results in a string-like network, expanding the slowing effects to a large portion of the system. When the network percolates, dynamics in the whole system is arrested, leading to a glass transition.

简  历：

2001年于中科院物理研究所获得博士学位；
2001年至2007年在美国Ames国家实验室做博士后和助理研究员；
2007年10月回国在中国人民大学任教。

先后从事包括表面生长动力学中表面纳米结构的形成和稳定性、微观原子扩散对表面形貌的形成机制、量子尺寸效应对表面纳米结构形貌和稳定性的影响、非晶合金等体系中过冷液态和玻璃态的微观结构、动力学性质和力学性质以及玻璃转变机制等的理论和计算机模拟研究。

邀请人：姚裕贵  教授 

联系方式：物理学院办公室（68913163）
网    址： http://physics.bit.edu.cn/