添加合金元素對6061鑄造鋁合金微結構與機械性質之影響

Effect of Alloying Element on the Microstructures and Mechanical Properties of 6061 Aluminum Casting Alloy

孫偉聖(Wei-Sheng Sun)

指導教授 ： 黃和悅

國立虎尾科技大學/工程學院/材料科學與綠色能源工程研究所/碩士(2012年)

https://doi.org/10.6827/NFU.2012.00005

摘要

本研究將針對6061鋁合金添加不同比例的合金元素，利用消失模鑄造法完成試樣後施以均質化退火及T6熱處理，再將處理完成的試樣進行成分分析、硬度試驗、微觀結構分析及機械性質測試，以瞭解不同釩含量對各項性質的影響。
實驗結果發現，釩的添加量增加其均質化退火所需的時間也需要增加，當釩含量超過1.11%之後皆在48小時即達到均質化效果。此外，隨著釩的添加量增加其所需的人工時效時間也會增加，且硬度會隨著時間的增加而提升。抗拉強度及降伏強度會隨釩的添加量增加而提高，但伸長量卻會隨之下降，以電子顯微鏡觀察試樣斷面發現，釩含量的增加其斷面上的韌窩組織會隨之減少而導致材料延性降低。在顯微組織觀察中發現，隨著釩的添加量增加，晶粒尺寸會隨之下降。以場發射掃描式電子顯微鏡進行觀察，發現各參數試樣皆在晶界處會產生析出相，未添加釩試樣的析出物以Al9Si、Mg2Si為主，而添加為0.657%及1.11%釩的試樣則為Al9Si、Mg2Si及Al3V，當添加為4.4%釩時則附加Al10V相。

關鍵字

6061鋁合金 ； 合金元素 ； 消失模鑄造法 ； 顯微組織 ； 機械性質

並列摘要

Vanadium modified aluminum grade A6061 alloys were manufactured by lost foam casting process. The homogenization, solution treatment and artificial aging schedules were optimized to obtain superior hardness and confirmed chemical composition within the crystals of the solid solution was uniform. Then, the effect of the modified alloys on the microstructure and mechanical properties were evaluated.
The results show that the time to achieve homogenization annealing increases with increasing of the alloy vanadium content. A minimum time necessary for a complete homogenization is 48 hours when the vanadium content exceeds 1.11%. As the vanadium element increases, the artificially aging time increases. Meanwhile, the hardness of modified alloy also increases remarkably with increasing vanadium content. Increasing vanadium content reduces ductility but increases tensile strength, yield strength and fatigue life. The SEM analysis of the tensile fracture surface shows that the tensile fracture surfaces show obvious dimple feature. With increasing vanadium additions, the dimple fracture translates into the mixed mode of quasi-cleavage and dimple fracture. The microstructure indicates that vanadium additions also effectively decrease the grain sizes. Besides, precipitates forming along the grain boundaries are found; most significant in Al-Mg-Si alloys are Al9Si phase and Mg2Si phase. It is found that vanadium additions can significantly promote the formation of Al3V phase at the grain boundaries. Since vanadium contains up to 4.4% that leads to the both Al3V phase and Al10V phase are present in the grain boundaries.

並列關鍵字

6061 Aluminum Alloy ； Alloying Elements ； Lost Foam Casting ； Microstructure ； Mechanical Properties

參考文獻

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