液态金属的结构演变及其与玻璃形成能力的内在关系研究

项目名称： 液态金属的结构演变及其与玻璃形成能力的内在关系研究

项目编号： No.U1532115

项目类型： 联合基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 王晓东

作者单位： 浙江大学

项目金额： 52万元

中文摘要： 液态金属的结构演变是采用凝固技术合成新材料的关键所在。受限于对液态金属结构的认识，当前很多研究仍主要集中在熔体物性的测量上，对其背后机理的了解还不是很清晰。本项目将选择多组合金体系，采用原位高能X射线衍射（XRD）和X射线吸收精细结构谱（XAFS）技术主要研究液态金属中液-液相变时的构型变化规律，不同玻璃形成能力的液态金属的结构特征及其动力学特性等。测量不同玻璃形成能力的金属玻璃在非晶态、过冷液态和过热金属熔体时原子构型随温度的变化规律，结合分子动力学(MD)和反蒙特卡罗（RMC）模拟，从团簇的角度分析非晶相、领先晶体相与液相间的结构联系。探索强玻璃形成能力金属玻璃在液相时的原子结构特征，建立液态金属原子排列和玻璃形成能力之间的关系，为认识、设计新型块体金属玻璃提供一定的理论指导。

中文关键词： 非晶合金；微结构；玻璃形成能力；X射线吸收精细结构

英文摘要： The structural evolution in liquid metals is a key point for preparing new materials by using solidification technique. So far, the majority of present studies are mainly focused on the measurement of physical properties of liquid metals. However, the mechanisms underlying the properties are not fully understood due to the limited knowledge to the stucture of liquid metals. In this project, we will select several representative alloy systems to study the structural evolution during the liquid-liquid transition, the structural characteristics and dynamics of liquid metals with different glass forming ability (GFA), etc. by using in situ high energy X-ray diffraction (XRD) and extended X-ray absorption fine structure (XAFS) techniques. The structure of metallic glasses (MGs) with different GFA will be examined in amorphous, supercooled liquid and overheated liquid states to gain the dependence of atomistic structure evolution with temperatures. Combining molecular dynamics (MD) with reverse Monte Carlo (RMC) simulations, the structure of liquid alloys and their correlations with high GFA will be explored by analyzing the structural relations among the amorphous phase, the precursor of crystalline phase and the liquid phase from clusters perspective. By studying the liquid structure characteristics of strong-GFA MGs, we attempt to build up the relationship between the liquid structure and the GFA for selected alloys, which could provide some hints to the recognition and design of new class of bulk MGs.

英文关键词： Amorphpous alloys;Microstructure ;Glass forming ability;X-ray absorption fine structure