| 摘要: | 共晶Al-Si合金（～12wt%Si）具有溶點低、鑄造性佳、質量輕、強度高、耐磨性佳與低熱膨脹係數等優點，已廣泛應用於活塞、煞車泵及泵浦等。隨著科技與工業的發達，對高性能且質輕的材料需求更勝以往，故常在共晶鋁矽合金中添加Cu、Mg元素來提升合金之熱穩定性與耐磨性。金全興公司接獲客戶生產耐高溫磨耗Al-Si合金訂單需求，客戶原本使用之材料，在鑄造狀態下，室溫下硬度值為HRB 70，但經300℃×100h熱處理後，硬度降為HRB 12~15。客戶需求在經過300℃×100h熱處理後，合金硬度仍能維持在HRB 30。由於合作企業受限於本身的研發能力，無法有效突破所面臨之鋁合金(耐磨耗Al-Si合金熱穩定性)困境，且因申請人長期從事Al-Si合金相關研究，於Al-Si合金之高溫熱穩定性與耐磨性已有初步學理探討。所以合作企業基於Al-Si共晶合金的低溶點、易鑄造特性，擬藉由國科會之協助，委請申請人進行本案之執行。期望本研究能達成應用需求，另外，申請人也期望能獲得清楚之學理依據，以供有價值之學術參考。由於共晶鋁矽合金中之Cu、Mg原子於凝固過程中，將依元素含量之不同而形成Al2Cu相(θ相)、Al5Cu2Mg8Si6相（λ相）及Mg2Si相（β相）等介金屬化合物。這些晶出相能強化鑄態合金之熱穩定性、能提升鋁矽合金鑄態時之硬度。本研究之先導研究發現，Cu對含Mg之Al-14.5Si合金“具有高溫（250℃）熱穩定性”。初步顯示，晶出相經250℃×20hr處理後仍然存在於鋁基地中，可維持合金之熱穩定性，但析出相呈現過時效現象。在40N荷重下，進行磨耗時，合金經250℃×20hr處理後硬度最高，具有最佳耐磨性。 Cu、Mg原子為Al-12Si共晶合金強化相組成元素，不同Cu含量將影響合金之微結構，就所收集文獻，並無研究含Mg之Al-12Si共晶合金在300℃下之熱穩定性、與針對Cu含量對合金析出強化效果影響之報導。故本研究擬於含Mg之Al-12Si共晶合金中，結合微結構觀察與機械性質測試探討：Cu含量對含Mg之Al-12Si共晶合金在鑄態及熱處理後之高溫（300℃）熱穩定性與耐磨性質之影響，期望本研究能達成應用需求外，也能在學理上供學界有價值之理論參考。 Al-Si Eutectic alloy (~ 12wt% Si) with a low melting point, excellent castability, light weight, high strength, wear resistance and low thermal expansion coefficient, etc., have been widely used in piston, brake pump and pump, etc. With the advance of technology and industry, the demand for high performance and lightweight materials than ever, Generally, Cu, Mg elements are added to Al-Si eutectic alloy to improve the thermal stability and wear resistance. JinQuanXing Co.LTD (joint venture) was asked to produce thermal atability Al-Si alloy by one of the customer. The order requirement is: the hardness still remained above HRB 30 after 300 ℃ × 100h heat treatment, insyead of HRB 12 . The joint venture subject to their R & D capability, can not effectively break the difficulties. Our grpup have engaged in some preliminary theoretical study related to thermal stability and wear resistance of Al-Si alloys. Therefore, joint venture requests us to the case of the execution, assisted by the National Science Council. We hope this research can be a useful help to industry ,and also hope to get clear of the theoretical basis for the valuable academic reference. During the solidification, Cu, Mg atoms in Al-Si eutectic alloy will form of Al2Cu phase (θ phase), Al5Cu2Mg8Si6 phase (λ-phase) and Mg2Si phase (β phase) and other intermetallic compounds. These phase can strengthen the thermal stability of the cast alloy. Our pilot study findings, alloys of Al-14.5Si containing Cu, Mg is high temperature (250 ℃) thermal stability. Under the 40N load, the wear after 250 ℃ × 20hr has the highest hardness and the best wear resistance. Cu, Mg atoms are the elements of strengthening phase in the Al-12Si eutectic alloy’ Alloys with various Cu content will affect the microstructure. According to the literature collection , no reports were found about both of thermal stability at 300 ℃ , and Cu precipitation strengthening effect on the alloy . The purpose of this study is to research the effect of Cu on the thermal stability and wear resistance of Al-12Si alloy containing Mg, through the combinationof micro-structure observation and mechanical properties testing. Hopefully, this research would not only reach the requirement of JinQuanXing Co.LTD, but also can be valuable in an academic theory of reference for scholars. 研究期間：10006 ~ 10105 |
