本研究主要探討鑭的添加量對6061鋁合金的顯微組織、硬度和電化學行為的影響。以真空熔煉鑄造技術製備不同添加量鑭（4wt.%、6wt.% 、8wt.%及10wt.%）的四種鋁合金，然後將它們固溶處理與人工時效。利用電子顯微鏡、能量色散光譜儀及X-射線繞射分析進行相分析，由XRD分析顯示添加鑭元素之試片會產生Al11La3相，其數量會隨鑭元素添加量增加而增多，而當鑭元素添加量超過4wt.%時，會形成LaSi2介金屬化合物。經由電化學實驗可以發現Al0.3Fe0.3Si0.5析出相會降低耐腐蝕性。添加鑭元素會使晶粒尺寸變小，並且得到較高的維氏硬度值。

In this study, the effects of different amounts of lanthanum on the microstructures, hardness and electrochemical behavior of 6061 aluminum alloys were investigated. Four different alloys containing various amounts of lanthanum (4, 6, 8 and 10 wt%) were prepared through the vacuum casting technique, and then they were solid solution treated and artificially aged. The phase composition and microstructure of the as-cast alloys were analyzed by X-ray diffraction and scanning electron microscopy with energy-dispersive spectroscopy. X-ray diffraction results showed that the addition of lanthanum had been found to format Al11La3 phases. Scanning electron microscopy micrograph and energy-dispersive spectroscopy analysis results showed that with increasing lanthanum, the Al11La3 phase volume fraction was increased. Lanthanum at higher content (above 4 wt%) in as-cast alloys formed intermetallic compound to be LaSi2. The results of the electrochemical tests showed the presence of Al0.3Fe0.3Si0.5 phase precipitates in aluminum alloy resulted in a reduction of its corrosion resistance. With lanthanum addition the grain size observed smaller, and gave a higher measured Vickers hardness.

摘要...i
Abstract...ii
誌謝...iv
目錄...v
表目錄...ix
圖目錄...xi
第一章 緒論...1
1.1前言...1
1.2研究動機與目的...2
第二章 理論基礎及文獻回顧...4
2.1鋁合金簡介...4
2.1.1鋁的歷史...4
2.1.2鋁的提煉...4
2.1.3鋁合金之種類與相關代號...5
2.1.4 6XXX系鋁合金之特性及應用...8
2.2鋁合金強化機制...9
2.2.1晶粒細化...9
2.2.2固溶強化...10
2.2.4析出強化...11
2.2.4散佈強化...12
2.2.5應變硬化...12
2.3合元素對鋁合金的影響...13
2.4鋁合金熱處理...15
2.4.1鋁合金熱處理之目的...15
2.4.2固溶處理...15
2.4.3時效處理...15
2.4.4 6061鋁合金熱處理...17
2.5真空感應鑄造(Vacuum Induction Melting, VIM)...18
2.5.1感應加熱原理...19
2.6鋁合金的腐蝕與電化學特性...22
2.7國內外相關研究...23
第三章 實驗方法...27
3.1實驗流程...27
3.2真空感應鑄造...29
3.2.1鑄造參數...29
3.3坩鍋及模具製備...30
3.3.1陶殼模坩鍋製備...30
3.3.2模具製備...33
3.4熔煉使用之儀器...35
3.5熱處理實驗...36
3.5.1熱處理流程...36
3.5.2熱處理使用儀器...37
3.6顯微組織分析...38
3.6.1顯微組織分析流程...38
3.7硬度試驗...39
3.7.1硬度試驗流程...39
3.7.2硬度試驗使用儀器...39
3.8掃描式電子顯微鏡及能量光譜儀分析...40
3.9 X光繞射儀(X-Ray Diffraction, XRD)...41
3.10電化學試驗...42
3.10.1電化學試驗流程...42
第四章 結果與討論...44
4.1顯微組織分析...45
4.1.1金相組織觀察...45
4.1.2晶粒大小觀察...52
4.2 SEM及EDS相成分分析...53
4.3 X光繞射分析...61
4.4微硬度分析...69
4.5電化學分析...70
4.5.1極化曲線分析...70
4.5.2腐蝕形貌組織觀察...72
第五章 結論...86
參考文獻...88

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