非晶形成能力与晶体生长行为的关系

项目名称： 非晶形成能力与晶体生长行为的关系

项目编号： No.51471108

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 李金富

作者单位： 上海交通大学

项目金额： 85万元

中文摘要： 非晶形成合金多属共晶体系，非晶形成能力的大小常与共晶共生生长与否联系在一起，但迄今为止尚缺乏足够的实验事实和坚实的理论分析支持这一论点。为此，本项目拟首先以容易获得大过冷度的Ni-、Pd-基二元共晶系非晶形成合金为对象，在较宽的成分范围内开展深过冷凝固实验，监测凝固过程中试样的温度变化，测定快速凝固阶段的晶体生长速度，分析凝固组织，建立凝固方式、晶体生长速度、固液界面结构特征与合金成分以及过冷度的关系，同时实验确定各成分合金的非晶形成能力，考察非晶形成能力是否与共晶生长方式间存在必然联系，并分析其缘由。其次，在上述二元共晶合金的基础上添加第三组元，考察晶体生长行为的变化情况及其对非晶形成能力的影响，并阐明其机制。相关研究工作的开展，将有助于完善非晶形成的晶体生长控制理论，并为包括第三组元选择在内的非晶合金成分设计提供理论依据。

中文关键词： 共晶合金；深过冷；非平衡凝固；晶体生长；微观组织

英文摘要： Most of glass-forming alloys belong to eutectic alloy systems. Glass-forming ability is naturally thought to be related with coupled eutectic growth. Such an argument, as yet, is far from proven by experimental results and theoretical analyses. In this project, Ni- and Pd-based binary eutectic alloys that can easily be undercooled up to high degrees will first be used for experimental investigation. The alloy melts within a wide concentration range will be solidified at different undercoolings. By monitoring the cooling curve, measuring the crystal growth velocity in rapid solidification and analyzing the solidification structure, dependences of crystal growth mode, atomic attachment kinetics and solid/liquid interface structure on the concentration and undercooling will be established. After the data of critical thickness for glass formation are experimentally determined, the relationship between glass-forming ability and crystal growth behavior will be examined and analyzed. Secondly, third elements will be added to the binary eutectic alloys to investigate what will happen in crystal growth behavior and glass-forming ability. It is believed that the investigation results are helpful for us to understand the crystal growth-controlled glass formation and improve the composition design theory of metallic glasses including the third element selection.

英文关键词： eutectic alloys;undercooling;non-equilibrium solidification;crystal growth;microstructure