(Zr48Cu36Al8Ag8)99.25Si0.75複材高溫塑性行為之研究; Thermalplastic forming ability of (Zr48Cu36Al8Ag8)99.25Si0.75 based composite

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題名:	(Zr48Cu36Al8Ag8)99.25Si0.75複材高溫塑性行為之研究;Thermalplastic forming ability of (Zr48Cu36Al8Ag8)99.25Si0.75 based composite
作者:	張漢宗;Han-Zong Zhang
貢獻者:	材料科學與工程研究所
關鍵詞:	高溫塑性行為;複合材料;金屬玻璃;high temperature plastic behavior;bulk metallic glass;composite
日期:	2011-07-26
上傳時間:	2012-01-05 12:24:33 (UTC+8)
摘要:	鋯基非晶質合金具有高強度、高硬度及優良的玻璃形成能力，並且在過冷液相區間擁有十分良好的超塑性變形能力，故在微機電系統以及奈米複印上具有發展之潛力。但有鑑於單一相鋯基非晶質合金之低塑性缺點，本研究採用前人研發具高塑性變形能力之鋯基金屬玻璃複材， (Zr48Cu32Al8Ag8Ta4)99.25Si0.75 為基材in-situ外加ex-situ 9 vol% Ta ，變形量可提升到34%。並藉由分析結果來探討添加Ta之鋯基金屬玻璃複材在熱壓印應用上之可行性。利用TMA及高溫壓縮試驗，探討該合金複材在過冷液相區之黏度及熱塑變形行為，由TMA分析結果可以得知(Zr48Cu32Al8Ag8Ta4)99.25Si0.75基複材的黏度隨溫度上升而下降，並在733K下會產生一穩定之黏性流。另外由不同溫度、不同應變速率下，之壓縮試驗，分析結果得知在溫度為764K及應變速率為5×10-2下，可獲得到最低的流變應力76MPa。而由XRD和TEM對高溫壓縮後之試片所進行結構分析，結果顯示該金屬玻璃複材經最高溫度及最低應變速率下之高溫壓縮試驗後仍能維持原有非晶的結構。最後，利用實驗所得參數進行雷射標籤的複印，以證實其超塑性能力。 Zr-based amorphous alloys have several attractive properties such as high strength, high hardness, good glass forming ability, and excellent ability of superplastic formation , so there is a development potential in MEMS and nanotechology. However the monolithic Zr-based amorphous alloys displays limited plasticity(0-0.5%) . In this study, the plasticity of (Zr48Cu32Al8Ag8Ta4)99.25Sio.75 based bulk metallic glass composite (BMGc) of 4 at% in-situ Ta and 9 vol% ex-situ Ta increases up to 34%. The viscosity and hot plastic deformation in supercooling liquid region were done by thermal mechanical analysis (TMA) and hot compression test. According to the TMA results, the viscosity of the bulk metallic glass composite (BMGc) decreases with temperature increase, and there is a stable viscous flow occurs at 733 K. The results of hot compression test under different temperatures and strain rates shows the lowest flow stress was obtained in the lowest strain rate(5×10-2s-1) under 764 K . Analyze micro structure of the specimens after hot compression test by XRD and TEM to check the amorphous state. All results reveal their amorphous state even under the highest temperature and the lowest strain rate which are 764 K and 5×10-2 s-1 respectively.
顯示於類別:	[材料科學與工程研究所 ] 博碩士論文

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