2008-08-012024-05-15https://scholars.lib.ntu.edu.tw/handle/123456789/664073摘要：形狀記憶合金(SMAs)因擁有形狀記憶效應(SME)，超彈性（PE）及不錯的制震能（DC），因而被視為機能材料，並廣泛應用於工程及醫學領域，是一個極具應用潛力的智慧材料。目前研究最透徹的TiNi SMAs其麻田散體變態溫度一般在60℃或以下，但由於微機電及醫學等領域應用上之需求，麻田散體變態溫度能在100~200℃間才有應用價值的，也因而100~200℃間之高溫SMAs之研究是有其必要性。主持人研究多年之TiNi基高溫SMAs，其中Ti50-yNi50Zr(Hf)y合金含Zr(Hf)量在20at%以下是有≦350℃之變態溫度的，唯其脆性使之無法加工而實用化；另Ti-Ni-Pd三元及Ti-Ni-Pd-X四元合金雖加工性較佳，但因貴金屬價昂而不致有應用價值。本計畫擬以二年期間，針對價較廉之NiAl基高溫SMAs來從事深入的研究，包括Ni63Al37二元及Ni-Al-Fe三元SMAs。首先利用合金設計尋求100~200℃變態溫度之適當成分之合金，由報導得知此等合金亦屬脆性材料，若能添加元素 (例如Fe,Mn等)及微化晶粒則可改善其脆性。本計畫擬尋求擁有適當延展性且又具高溫SMAs性能之NiAl基二元/三元合金，並擬由粉末冶金(P/M)及傳統VAR熔煉方法來加以製備，包括粉末顆粒大小、反應燒結之最佳條件以及其後之熱處理等，都將一一加以探討。此外，由P/M及VAR製備之SMAs的變態點、SME/PE及顯微組織及結構也將深入了解，並由此研究出價廉且擁有優異性能之NiAl基高溫SMAs。而本計畫開發之高溫SMAs在學術上可以進一步了解P/M反應燒結對SMAs性能之影響，也能使SMAs之工程應用潛力更加擴大。<br> Abstract: The characteristics of shape memory effect (SME), superelasticity (PE) and high damping capacity (DC) exhibited in TiNi shape memory alloys (SMAs) are usually considered TiNi SMAs to be smart materials and they have high potential for applying in the engineering field. However, the shortage of TiNi SMAs is that their transformation temperature, Ms, is not higher than 60oC and thus restricts their applications in MEMS, medical fields, etc. The purpose of this 2-year project is looking for the NiAl high temperature SMAs which have the Ms temperature in the range of 100~200oC. According to our past experience on the studies of high-temperature SMAs, Ti50-yNi50Zr(Hf)y SMAs have Ms:50~350oC with y:0~20at%, but their intrinsic brittleness limits the practical engineering application. Ti50Ni50-xAux and Ti50Ni50-xPdx SMAs have better working ability than Ti-Ni-Zr(Hf) SMAs, but are expensive and do not have SME in the range of x:10~30at% due to different martensitic transformations exhibited in Ti50Ni50 and Ti50Pd50 SMAs. In this project, we will study binary and ternary Ni-Al high temperature SMAs which have the Ms temperature in the range of 100~200oC. In order to improve the intrinsic brittleness, boron, iron and rare earth(Re) will be added in these designed Ni-Al SMAs. Powder metallurgy(P/M) and/or conventional casting methods will be used to prepare these SMAs in which the powder size, the reactive sintering condition and the suitable heat treatment will be investigated. At the same time, the Ms temperature, microstructure and SME/PE/DC characteristics associated with these designed Ni-Al SMAs will also be studied. From experimental results, the beneficial properties of Ni-Al SMAs fabricated by P/M method will be more understood, as compared to those prepared by conventional casting method. Accordingly, Ni-Al high temperature SMAs with good characteristics will be fabricated from P/M method and these SMAs could have wider engineering application in the near future.高溫形狀記憶合金粉末反應燒結NiAl基二元/三元合金Ms溫度High temperature shape memory alloysP/M reactive sinteringNiAl binary/ ternary alloysMs temperature