| 摘要: | 藉由光學顯微鏡(OM)、導電度(%IACS)、差式掃描熱分析儀(DSC)、掃描式電子顯微鏡(SEM)、場發射電子微探儀(FE-EPMA)進行微結構觀察與成分分析，以穿透式電子顯微鏡(TEM)及機械性質(硬度、拉伸)試驗等，探討銀含量(≦0.7wt.%Ag)與頂時效熱處理(T6)對高強度可熱處理型 AA2040（Al-5.1Cu-0.9Mg-Ag）鍛造鋁合金微結構與機械性質之影響。
結果顯示，微量銀並不會對鑄態、均質化、熱輥、與固溶淬火（T4）等之金相微結構造成不同之影響，鑄態合金微結構係由共晶θ(Al2Cu)、S（Al2CuMg）與少量的富鐵相(Al15(FeMn)3(CuSi)2)所構成;均質化後，共晶θ(Al2Cu)及S（Al2CuMg）相幾乎皆回溶於基地中，而(Al15(FeMn)3(CuSi)2) 富鐵相並無法藉由均質化熱處理來消除。熱輥後經固溶處理時，銀元素並不會對合金再結晶程度有所影響，但可增加合金固溶淬火態（T4）中的溶質原子(Cu、Mg等）之固溶量，並使合金之主要強化相由S′ (Al2CuMg)相轉為Ω(Al2Cu)相;亦發現當銀含量增加時，合金頂時效（T6）之Ω(Al2Cu)相析出量與合金強化相總析出量（Ω+S′＋θ′）均隨之增加，提升了合金析出動力，且Ω(Al2Cu)相比S′（Al2CuMg）相具有更佳之強化機械性質效果，因而提升了合金於頂時效(T6)時的強度;雖然含Ag合金之延性略低於未含Ag合金，但所有Al-5.1Cu-1.0Mg-Ag合金都具有良好之延性(>10%)，其拉伸破斷面形貌皆呈現凹窩(dimple)之韌斷特徵。
;Microstructure observation and composition by optical microscope (OM), electrical conductivity (%IACS), differential scanning thermal analyzer (DSC), scanning electron microscope (SEM), field emission electron microprobe (FE-EPMA) Analysis, through transmission electron microscopy (TEM) and mechanical properties (hardness, tensile) test, etc., to explore the silver content (≦0.7wt.% Ag) and heat treatment (T6) on high-strength heat-treated AA2040 (Al-5.1Cu-0.9Mg-Ag) the effect of forged aluminum alloy microstructure and mechanical properties.
The results show that trace amounts of silver will not have different effects on the microstructures of as-cast, homogenized, hot roller, and solution quenching (T4). The microstructure of the as-cast alloy consists of eutectic θ (Al2Cu),S (Al2CuMg) and a small amount of iron-rich (Al15(FeMn)3(CuSi)2); after homogenization, the eutectic θ (Al2Cu) and S (Al2CuMg) phases are almost dissolved back into the matrix, while The iron-rich (Al15(FeMn)3(CuSi)2) phase cannot dissolved back into the matrix by homogenization heat treatment. When the solution treatment is performed after the hot roller, the silver element will not affect the recrystallization degree of the alloy, but it can increase the amount of solute atoms (Cu, Mg, etc.) in the alloy solution quenched state (T4), and The main strengthening phase of the alloy was changed from S′(Al2CuMg) phase to Ω (Al2Cu) phase; when the silver content was increased, the precipitation amount of Ω (Al2Cu) phase of alloy top aging (T6) and the total precipitation amount of alloy strengthening phase were also found (Ω + S′+ θ′) all increase, which improves the precipitation power of the alloy, and the Ω (Al2Cu) phase has a better effect of strengthening mechanical properties than the S′(Al2CuMg) phase, thus improving the alloy′s top aging (T6) Strength; although the ductility of Ag-containing alloys is slightly lower than that of non-Ag-containing alloys, all Al-5.1Cu-1.0Mg-Ag alloys have good ductility (> 10%), and their tensile fracture surface morphologies are all Presents the characteristic of dimple rupture. |
