Microstructures and thermal stability of metastable - phase precipitates formed in an Al – Cu alloy at 463
نویسندگان
چکیده
The precipitation behavior in an Al– Cu alloy isothermally annealed at 463 K was studied using Vickers microhardness tests, differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). An additional endothermic peak found in the DSC measurements may be attributed to the h00-phase, independent of the dissolution of the G. P. (II) and the h00-phase at the aging temperatures. High-resolution transmission electron microscopy (HRTEM) revealed that the G. P. (I) is formed at a very early stage of isothermal aging, even at 463 K. Comparing the Vickers microhardness and TEM images, it was concluded that the stage at which the G. P. (II) and h00-phases precipitated simultaneously is mainly responsible for the peak hardness.
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