Effects of copper wheel rotation speed and Scandium content on the characteristics of Al-Y-Ni amorphous ribbons
| Autor: | Wei-Sheng Hsu, 許瑋陞 |
|---|---|
| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 Effects of solidification rate and scandium addition to Al-Y-Ni amorphous alloy were investigated in this study. The multi-component alloy ribbons with different thickness and compositions of (Al0.87Y0.08Ni0.05)100-XScX (x=0, 1, 2 at%) were prepared by single roller melt-spinning method by changing either the rotation speed of copper wheel in the range of 4000rpm to 1000rpm. All compositions of alloy ribbons were confirmed amorphous by XRD in the rotation speed of copper wheel in the range of 4000rpm to 2000rpm, and when the rotation speed of copper wheel was 2000rpm, all compositions of alloy ribbons were nano-crystallites structure by SEM observations, and with the addition of Scandium increased the refinement of grain size was gave rise, but when the rotation speed of copper roller was 1000rpm, all compositions of alloy ribbons were had α-Al crystalline phase appeared by XRD. The microhardness of alloy ribbons appeared to increase with additions of Scandium increased, and the maximum hardness was 448.3Hv when Scandium contain was 2at% and the rotation speed of copper roller was 2000rpm. The analysis of thermal properties were measured by differential scanning calorimetry (DSC), when the rotation speed of copper roller was 4000rpm, the compositions of Al87Y8Ni5 and (Al0.87Y0.08Ni0.05)99Sc1 alloy ribbons had supercooled liquid regions was 24.7K and 23.2K respectively, and the thermal stability of all compositions alloy ribbons appeared to rise with the concentration of Scandium. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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