AA2024 Al-Cu-Mg高強度鋁合金中添加微量銀對奈米析出物之演變
Other Title
The Effects of Minor Ag Addition on Nano-precipitates Evolution in an AA2024 Al-Cu-Mg High-strength Aluminum Alloy
Journal
金屬熱處理
Journal Issue
160
Start Page
17
End Page
27
Date Issued
2024-03
Author(s)
戴正凌
Abstract
本研究探討了於AA2024 Al-5.1Cu-1.0Mg高強度鋁合金中添加微量Ag（0.4 wt.%），其於185°C時效各階段，奈米析出物Ω相與S相之演變與互相之影響。研究發現，添加Ag後產生之Ω相除了本身具有熱穩定性外，Ω相的形成能在11小時至18小時階段抑制S相粗化，使材料於過時效階段能維持強度。透過研究團簇物發現，其原因為大量生成之Ω相能加速消耗鋁基地中的Cu-Mg團簇物，使S相不易粗化。此外，於長時間（100小時）高溫時效下（185°C），Ω相最大厚度達到3nm後便不再粗化。藉由球差校正之高解析掃描式穿透電子顯微鏡分析Ω相原子排列，發現是因為Ag原子僅會偏析於Ω相與（111）_(Al)相接之兩側，兩端處則無，因此形成高縱橫比之現象，利於阻礙差排滑移。期待能利用其高溫穩定性採取溫成型之製程方式，運用在航太以及汽車產業上，藉此降低鋁合金冷加工製造之困難與成本。
In this work, the effects of minor Ag addition (0.4 wt.%) in AA2024 an Al-5.1Cu-1.0Mg high-strength aluminum alloy on the evolution of Ω phase and S phase have been investigated. It has been found that the Ω phase formed by the addition of Ag prevents the S phase from coarsening because the large amount of Ω phase formation accelerates the consumption of Cu-Mg clusters in the aluminum matrix. Therefore, the alloy could maintain its strength at the over ageing stage. In addition, the Ω phase is highly thermal stable that it stops coarsening after reaching 3 nm in thickness under a long-time (100 h) ageing treatment. The atomic arrangement of the Ω phase was analyzed by Cs-corrected high-resolution scanning transmission electron microscope. The high thermal stability is due to Ag segregation only on the interface between Ω phase and (111)_(Al), but not at the two sites. Thus, the high aspect ratio Ω phase can effectively interrupt the movement of the dislocation. It is expected that its high thermal stability can be utilized to warm forming process, which can be applied to the aerospace and automotive industries to reduce the difficulties and costs of cold working aluminum alloy manufacturing.
Subjects
AA2024鋁合金
球差校正掃描式穿透電子顯微鏡
微量銀添加
高溫穩定Ω相
S相
AA2024 high-strength aluminum alloy
Cs-corrected high resolution scanning transmission electron microscope (Cs-corrected HRSTEM)
Minor silver addition
Thermally stable Ω phase
S phase
Type
journal article