超高强钴硼基块体非晶合金的原子结构特征和增韧机理

项目名称： 超高强钴硼基块体非晶合金的原子结构特征和增韧机理

项目编号： No.51501166

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 王剑锋

作者单位： 郑州大学

项目金额： 20万元

中文摘要： Co-B基块体非晶合金是已知强度最高的块体金属材料，它们在微机电系统和精密加工领域具有应用潜力。目前，块体非晶合金的脆性问题是限制其使用的主要因素。已有的研究表明，成分调整能改善此类合金自身剪切变形能力，起到增韧的作用，然而，其内在的增韧机理尚不清楚。本项目拟从原子尺度结构的角度阐述合金的增韧机理。在前期合金开发的基础上，采用先进同步辐射X射线实验和第一性原理分子动力学模拟相结合的方法解析三元Co-B-Ta非晶合金的原子结构特征；详细研究原子短程序（团簇类型）、中程序（团簇排列和连接方式）以及自由体积（含量和分布）等结构因素对于合金韧性的影响；建立“成分-原子结构-韧性”之间的内在联系，揭示合金成分调整增韧Co-B-Ta块体非晶合金的机理。本项目的研究将有助于新型韧性超高强块体非晶合金的设计和开发，促进非晶合金在工程结构材料领域的应用。

中文关键词： 钴硼基块体非晶合金；增韧机理；原子结构；同步辐射；第一性原理分子动力学

英文摘要： Co-B-based bulk metallic glasses (BMGs) have huge potential for the application in the micro electro-mechanical system and precise machining field because of their higher strength than other bulk metallic materials known so far. However, the brittleness problem for this class of alloys limits their use for structural applications. Although previous researches have shown that the shear deformation ability and ductility can be improved by tuning the alloy composition, the intrinsic self-toughening mechanism is unclear. In this project, we will investigate the toughness mechanism of Co-B-based BMGs from the perspective of atomic-level structure. The atomic structure of ternary Co-B-Ta amorphous alloys will be resolved by the combination of advanced synchrotron radiation X-ray experiments and ab initio molecular dynamics simulations. The effect of structural indicators including short-range order (type of clusters), medium-range order (arrangement and connection of clusters) and free volume (fraction and distribution) on the ductility will be studied in detail. With the aim of better understanding the toughness mechanism of Co-B-Ta BMGs, the relationship of composition, atomic structure and ductility will also be established. These results obtained above will help to develop new superhigh strength BMGs with good ductility, and thus promote the application of amorphous alloys in the field of engineering materials.

英文关键词： cobalt-boron-based bulk metallic glasses;toughness mechanism;atomic structure;synchrotron radiation;ab initio molecular dynamics