金属非晶形成熔体的结构特征

项目名称： 金属非晶形成熔体的结构特征

项目编号： No.50871062

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 边秀房

作者单位： 山东大学

项目金额： 39万元

中文摘要： 利用高温X射线衍射仪、高温黏度仪等实验手段，研究了金属非晶形成熔体的结构特征及物理性质，主要取得如下几方面成果： 1. 揭示了金属玻璃形成熔体的结构特点及结构弛豫特点。在13种非晶形成能力不同的金属熔体的团簇原子配位数和脆性系数试验研究中，发现金属熔体的玻璃形成能力依赖于过热熔体的脆性而不是粘度值。用原子配位数随温度的变化率描述了熔体结构的驰豫特点。发现过热熔体脆性参数M和原子配位数随温度的变化率呈线性关系。 2. 建立了La基和Sm基非晶合金过热熔体脆性和过冷液体脆性的联系。试验发现，过冷液体脆性参数（m）和约化玻璃转变温度（Tg/Tl）成正比例关系，建立了过热熔体脆性（M）和过冷液体脆性（m）的关系。 3. 发现Al-Ni-M(M=La,Pr,Nd)金属玻璃熔体存在强- - 脆转变现象。 4. 发现金属玻璃边缘形成合金的熔体脆性越小，越有利于玻璃形成。在Al84Ni10Ce6合金中，加入相似元素La，Al84Ni10(Ce3La3)合金过热熔体脆性减少，同时其非晶形成能力得到显著提高。还发现，热熔体脆性的概念不仅适用于金属玻璃形成能力强的合金，也适用于玻璃形成边缘合金。

中文关键词： 金属熔体；熔体结构；金属非晶

英文摘要： We studied the structural feature and the physical properties of the metallic glass-forming melts by using a high temperature X–ay diffractometer and a high temperature viscosity meter. The main results are as follows. 1. The structural feature and the structural relaxation of the metallic glass-forming melts have been brought to light. Using 13 kinds of the metallic melts possessing different glass-forming ability, the coordination numbers of clusters and fragility of the melts were studied by the experiments. We found that the glass-forming ability of the metallic melts depend on the fragility of the superheated melts rather than their viscosity. The structural relaxation feature of the melts is described by the change rate of atomic coordination of clusters with temperature. The linear relationship between the fragility of the superheated melts, M, and the change rate of the atomic coordination with temperature. 2. We established a relationship between the superheated melt fragility and the supercooled liquid fragility for the La based alloys and Sm based alloys. The results of experiments shows a directly proportional relation between the supercooled liquid fragility parameter, m, and the reduced glass transition temperature. We also found out the relationship between the superheated melts fragility and the supercooled liquid fragility. 3. A important Strong-fragile transformation phenomena was found out in the metallic glass-forming melt of Al-Ni-M(M=La,Pr,Nd) alloys 4. We discovered the smaller, the melt fragility for the margin glass-forming alloys, the better the glass-forming ability. Adding similar atomic size elements in Al84Ni10Ce6 alloy, for example, La, We found that the superheated melt fragility of the Al84Ni10(Ce3La3) alloy decreases and the glass-forming ability of this alloy decreases greatly. The experimental results shows that the new concept of the superheated melt fragility is not only suitable for the better glass-forming alloy melts, but also for the margin glass-forming alloy melts.

英文关键词： Metallic melts; Melt structure; Metallic glasses