A384鋁合金矽含量高，液相具有良好的流動性，鑄造性佳，且由於耐高溫、耐磨耗及輕量化之特性，適合應用於風力發電設備中的鼻錐罩和機艙罩。本研究以A384鋁合金經退火後(BM材)施以摩擦攪拌製程(FSP材)處理進行表面改質，並對BM材和FSP材進行人工時效熱處理，探討經摩擦攪拌製程對A384鋁合金的磨耗性質影響。
A384鋁合金之組織，除了-Al樹枝狀晶外，另包括共晶Si顆粒、τ1(Al9FeNi)、Al3CuNi和Q (Al5Cu2Mg8Si6)等晶出相。由顆粒沖蝕磨耗結果顯示，本實驗各條件之最大磨耗率皆發生於低角度之斜向沖蝕磨耗，代表A384鋁合金有典型的延性磨耗特徵。BM材的晶出相分佈集中，樹枝狀晶的主幹和枝臂形成軟質區，容易受到沖蝕顆粒的切削，磨耗阻抗較低。經摩擦攪拌製程改質後，硬度提升，晶出相細化且均勻分佈，降低脆性龜裂的現象發生，有助於改善A384鋁合金的磨耗性質，其中，亦發現在沖蝕溝槽附近有殘留和脆性破裂之共晶Si顆粒和Al3CuNi晶出相，推測此兩相為A384鋁合金中有助提升磨耗阻抗的第二相；而τ1(Al9FeNi)晶出相則容易受到沖蝕顆粒的切削而被沖蝕顆粒移除，增加材料的重量損失，推測τ1(Al9FeNi)晶出相為A384鋁合金中較不耐磨耗的晶出相。在人工時效熱處理後，硬度的提升，增加材料的變形阻抗，導致最大沖蝕磨耗率下降；且由於延性下降，最大磨耗率角度向右偏移角度5，表示有脆性破壞特徵之傾向。

Lightweight A384 aluminum alloy with high silicon content has good casting property for its good flowing of the liquid phase. Due to the advantages of high temperature and high erosion resistances, it can be used in the main carrier of the wind turbine. The as-cast A384 aluminum alloy with full-annealed treatment (represented as BM) was used as the base metal in this study. The BM specimens with friction stir processing (FSP) and peak aging treatment after FSP were used for studying the erosion properties of these specimens.
It is recognized that four segregate phases are exhibited in the casting A384 alloy, including Si particles, τ1 (Al9FeNi), Al3CuNi) and Q (Al5Cu2Mg8Si6) precipitate phases. According to the experimental results, all of the specimens show a higher erosion rate at the oblique erosion impact angle. This phenomenon reveals that a characteristic of the ductile erosion. The second phases are precipitated and aggregated within DAS in the BM specimens that are easily to form a soft zone. The increasing erosion rate is owing to the soft zone cut by the erodent. Instead, the erosion resistance is increased after FSP. The refined and uniformly distributed second phases, which are resulted from the FSP, can help to increase the hardness and further reduce the brittle fracture of the specimens. Si and Al3CuNi) phases are usually found near or end of the grooves with little fracture. But the τ1 (Al9FeNi) phase is easier to be removed by the erodent cutting. It can be inferred that Si and Al3CuNi) are useful to improve the erosion resistance of A384 aluminum alloy, but τ1 (Al9FeNi) phase is detrimental for the erosion resistance of A384 aluminum alloy. Moreover, the maximum erosion of the BM and FSP specimens after peak aging treatment will be decreased. The hardness and the deformation resistance of peak aged specimens are increased. They have a brittle fracture tendency that the maximum erosion rate transfers 5 degree with decreasing ductility.

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