臺灣博碩士論文加值系統

本研究使用AZ91鎂合金作為基材， Al0.5CoCrFeNi2高熵粉末為強化相，以熱壓粉末冶金的方式製造鎂基複合材料。實驗中在AZ91合金中摻雜5 wt. %、10 wt. %、15 wt. %及30 wt. %的高熵粉末(粒徑為10 μm)，探討摻雜量對合金強度的影響；本研究也使用10 μm及90 μm之高熵粉末(摻雜量固定為10 % wt. %)，探討粉末粒徑對AZ91合金硬度的影響。
結果顯示，不同摻雜量之Al0.5CoCrFeNi2高熵粉末鎂基複合材料，其組成均為α-Mg、Mg17Al12、Al-Mn析出物和Al0.5CoCrFeNi2。粉末冶金過程中並未使AZ91與高熵粉末產生相變化。壓縮測試結果顯示，摻雜5 % 10 μm之高熵粉末，使極限抗壓強度45.73 MPa之AZ91增強至150.45 MPa。硬度測驗結果表明摻雜高熵粉末之複合材料硬度皆有增強之效果，摻雜粒徑10 μm高熵粉末之複合材料硬度由55.4HV增強至139.3HV，而摻雜90 μm高熵粉末之AZ91硬度低於摻雜10 μm高熵粉末之AZ91，其硬度為108.6HV。

In this study, 10 wt. % of Al0.5CoCrFeNi2 high entropy powder with the size of 10 μm and 90 μm were added to AZ91 alloy by powder metallurgy. According to the result of hardness and compression strength, particle size of 10 μm was the best candidate. Magnesium-based composites were then fabricated with four different addition amount (5 wt. %, 10 wt. %, 15 wt. %, 30 wt. %) to study the effect. The analysis was then carried out using SEM, XRD, MTS dynamic testing and Vickers hardness.
The experimental results showed that the phase composition of magnesium-based composites with different addition amounts are composed of α-Mg, Mg17Al12, Al-Mn precipitates and Al0.5CoCrFeNi2. The microscopic results show that the high entropy powder did not change the phase structure within the composite during the powder metallurgy process. In the compression test results, addition of 5wt. % 10 μm will increase the maximum compressive strength and yield strength from 45.73MPa to 150.45Mpa and 42.5MPa to 149.9Mpa, respectively. The hardness test showed that the hardness of the composite with high entropy powder were enhanced. The hardness of adding 10 μm is enhanced from 55.4 HV to 139.3 HV, while the addition of 90 μm result the lower hardness of 108.6HV.

摘要 I
Abstract II
目錄 IV
圖目錄 VII
表目錄 IX
第一章 前言 1
第二章 文獻回顧 3
2.1鎂與鎂合金的簡介 3
2.1.1鎂的介紹 3
2.1.2鎂合金的介紹 4
2.1.3鎂合金的命名方法 5
2.1.4合金元素對鎂合金的影響 6
2.1.5 AZ91鎂合金 8
2.2鎂基金屬複合材料 9
2.2.1鎂基金屬複合材料簡介 9
2.2.2摻雜SiC之鎂基金屬複合材料 9
2.2.3摻雜Al2O3之鎂基金屬複合材料 11
2.2.4摻雜TiB2之鎂基金屬複合材料 12
2.2.5摻雜金屬玻璃之鎂基金屬複合材料 12
2.2.6鎂基複合材料製備方法 13
2.3材料的強化機制 14
2.3.1 細晶粒尺寸強化 14
2.3.2固溶強化 14
2.3.3應變硬化 15
2.3.4散佈強化 15
2.3.5析出硬化 15
2.3.6熱膨脹係數差異的影響 16
2.3.7荷仔傳遞作用 16
2.4高熵合金的簡介 17
2.5高熵合金強化機制 18
2.6 AlxFeCoCrNi高熵合金的介紹 19
2.7高能球磨法 21
2.7.1高能球磨原理 21
2.7.2高能球磨之參數 22
2.7.3球磨製程之複合材料 23
2.8熱壓成型 24
2.9文獻回顧心得與研究動機 25
第三章 實驗步驟 26
3.1實驗流程 26
3.2實驗材料製備 27
3.3高能球磨法製程 28
3.4熱壓成型 30
3.5分析儀器 32
3.5.1粒徑分析儀 32
3.5.2 X光繞射儀 33
3.5.3場效發射式掃描電子顯微鏡 34
3.5.4維克氏硬度試驗機 35
3.5.5落地式動態材料試驗機 36
第四章 結果與討論 37
4.1原始材料分析 37
4.1.1 AZ91粉末 37
4.1.2 Al0.5CoCrFeNi2高熵粉末 41
4.2 高能球磨AZ91粉末 43
4.2.1 粒徑分析 43
4.2.2相分析 44
4.3熱壓成型複材錠 46
4.3.1孔隙率分析 46
4.3.2相分析 47
4.3.3顯微結構分析 49
4.3.4壓縮測試分析 56
4.3.5硬度分析 58
4.4討論 60
第五章 結論 62
參考文獻 63

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