In the near couple years, the applications of amorphous alloys have attracted great attention due to their characteristics and future potential. This research is intended to synthesis a lighter Mg-based amorphous alloy as the imprinting materials for micro-electromechanical system (MEMS) with a high glass forming ability (GFA) and lower glass transition temperature (Tg). Also, the workability of the Mg-based metallic glasses is examined in terms of several viscous flow behaviors and parameters obtained from the thermomechanical analysis (TMA).
The lighter Mg-based metallic glasses exhibit their superior glass forming ability, and can be cast into bulk metallic glasses (BMGs). Based on the thermal analysis of the Mg-Cu-Y glassy materials, the evaluation of the glass forming ability and thermal stability for searching the optimum alloy composition is conducted. By using Mg58Cu31Y11 amorphous alloy with the best composition as the micro-forming specimens, imprinting was made by hot pressing at 150oC with several applied compressive stresses to form the hexagonal micro-lens arrays. Finite element simulation using 3D Deform software is also applied to trace the microforming evolution, and to compare with the experimental observations. The results demonstrate that the imprinting is feasible and promising.
On the other hand, the Mg-Cu-Gd BMGs with even better GFA than Mg-Cu-Y are explored in terms of their thermomechanical properties. Extension of this study is performed partially by Cu replacing by Ag or B for the improvement of maximum diameter and thermal stability. And the workability of these Mg-Cu-(Ag, B)-Gd metallic glasses, namely, Mg65Cu25-xAgxGd10 (x = 0, 3, 10 at %) and Mg65Cu22B3Gd10 is evaluated in terming of the thermomechanical parameters, viscous flow behavior, deformability, and the deformation model. It is found the fragility for viscous deformation would increase with the replacement of Ag or B, leading to the negative factors for the micro-forming and nano-imprinting practices. This conclusion is supported by the many extracted parameters.
Thus, even the B-additive Mg based BMG has much higher hardness and Ag-additive Mg based BMG has the larger maximum rod diameter, they are more difficult to be formed, appearing as a negative factor in the micro-forming or nano-imprinting industry. The base Mg65Cu25Gd10 alloy stilly appears to be more promising than the Ag or B-containing alloys when the viscous forming is under consideration.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0710108-171128 |
| Date | 10 July 2008 |
| Creators | Chang, Yu-Chen |
| Contributors | Jang, Shian-Ching, Kao, Po-We, Huang, Chih-Ching, Hsieh, Ker-Chang, Pan, Cheng-Tang, Chen, Ming |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0710108-171128 |
| Rights | unrestricted, Copyright information available at source archive |
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