| dc.description.abstract | 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. | en_US |