Effect of nanostructure on phase transformations during heat treatment of 2024 aluminum alloy

In this work, we studied the transformations involving coherent (θ”/S”), semicoherent (θ’/S’), and incoherent (θ/S) precipitates (θ = Al 2 Cu, S CuMg) formed during heat treatment of an annealed nanostructured powder 2024 produced by cryogenic milling. These form over a wide temperature range (300–500 °C) depending on chemical composition. They influence grain growth sintering may facilitate formation fully dense material. Mechanical milling was performed for 20 h at to obtain particles. The structural evolution morphology particles were investigated three particle size ranges (<25, 25–45, 45–90 μm). Heat milled different temperatures (475, 500, 525 5, 10, 15, min. Morphological analysis as-milled using scanning electron microscopy indicated that process not completed. X-ray diffraction yielded θ volume fractions heat-treated powders. DSC precipitation dissolution GP (Guinier-Preston zone), coherent, heating as-atomized Accumulation deformation energy is suggested lead early transformation phases in finer powder.