Prediction of the Metallic Glass Formation Regions for the Ag-Al-Cu-Zr Quaternary System by the Calculation of Phase Diagram (CALPHAD) Method

• Main Authors: Hsien-Ming Hsiao, 蕭憲明
• Other Authors: Yee-wen Yen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/20197289621567324183

博士 === 國立臺灣科技大學 === 材料科學與工程系 === 103 === Bulk metallic glasses (BMGs) have excellent potentials for various applications due to their excellent mechanical properties. But the fundamental investigations of metallic glasses are scarce in Taiwan, most of which are focusing on mechanical tests. The determination of metallic glass formation region was not studied ever. Therefore, the main purpose of this study focuses on the prediction of formation of metallic glasses by means of thermodynamic calculation, which is commonly used in the CALPHAD field. First of all, it is necessary to establish a reasonably correct thermodynamic dataset, which is consistant with experimental reusutls, such as phase equilibria, enthalpy of formation or activities of liquid or solid. Then the related metastable phase diagrams of binary or ternary systems could be introduced and drawn to predict formation of metallic glasses regions. The Cu-based alloys are inexpersive, and Zr- and Cu-based alloys have promising ability to form amorphous metallic glasses due to their wide range of the supercooled liquid region. Those alloys are favorable for application in industries. In this study, the Ag-Al-Cu-Zr quaternary and subternary systems are investigated thermodynamically to determine the formation of metallic glasses regions. Furthermore, once formation compositions of metallic glasses were predicted correctly, only few alloy samples were needed to be verified experimentally. Thus the expense and time of metallic glasses research woul be largly eliminated. Also the application of metallic glasses would be promoted and accepted in industries.