腐蝕對2024鋁合金之機械性質影響

The Effects On Mechanical Properties of 2024 Aluminum Alloy Due To Corrosion

林毓書(Yu-Shu Lin)

指導教授 ： 單秋成

國立臺灣大學/工學院/機械工程學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.01316

摘要

鋁合金2024-T3為目前廣泛使用的航太材料，優點為高強度、質輕，但具有低抗蝕性；本文乃以行政院飛航安全委員會調查之「機腹蒙皮77公分裂紋事故」為案例研究，探討「腐蝕」對於飛機蒙皮材料2024-T3鋁合金之材料機械性質的影響。實驗分別針對腐蝕的破壞機制：靜態腐蝕、應力腐蝕以及腐蝕疲勞進行實驗。在靜態腐蝕實驗中，會將蒙皮材料製作成標準拉伸試片，並透過設定不同的環境參數，將試片浸泡於各腐蝕環境參數中，而後對試片進行拉伸實驗求取其相對應的應力應變曲線，檢視腐蝕是否會對試片造成機械性質的改變，並探討各環境因素對蒙皮材料的強度影響程度。在應力腐蝕實驗中，由前述的環境因素加上固定的張應力，探討施加應力對於腐蝕破壞的影響。腐蝕疲勞的部份中，則是將蒙皮製做成標準疲勞試片以及微型疲勞試片，透過觀察裂縫生長，比較蒙皮在空氣中以及腐蝕環境中之裂縫生長速率的差異性，並比較標準疲勞試片與微型疲勞試片所反映出的數據結果之異同，以研究微型疲勞試驗機用於疲勞測試的可行性。

關鍵字

鋁合金2024-T3 ； 應力腐蝕 ； 腐蝕疲勞 ； 疲勞裂縫生長 ； 微型疲勞試片

並列摘要

2024-T3 Aluminum alloy is a wildly-used material in aerospace, for it’s high strength and low density, but with a low-corrosive resistance. This study tries to find out the effects on mechanical properties of 2024-T3 Aluminum alloy due to corrosion, which is based on an accident “ CI 7552-77cm crack accident” investigated by Aviation Safety Council (ASC) . This experiment is separated into three parts: static corrosion, stress corrosion cracking and corrosion fatigue. In static corrosion, we prepare tensile specimens which are exposed to different corrosive environments, then construct the relative stress-strain curve after tensile test to check whether the tensile strength changes due to corrosion, and discuss how it has changed for different environment factors. In stress corrosion cracking, we introduce the “tensile stress” factor in addition to the previous corrosive environments, discuss the effects on mechanical properties under corrosive environments when the tensile stress is added. In corrosion fatigue, we prepare standard CT specimens and miniature fatigue specimens, then through observing the crack grows, compare the difference in crack growth rate between non-corrosive environments and corrosive environments, and compare the results between CT specimens and miniature specimens, as well, for checking the usage and practicability of miniature fatigue specimen testing.

並列關鍵字

2024-T3 Aluminum ； Stress Corrosion Cracking ； Corrosion Fatigue ； fatigue crack growth ； miniature fatigue specimens

參考文獻

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