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چکیده
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In the present research work, the hydro-mechanical deep drawing (HMDD) process of 2024 aluminum alloy is performed experimentally and numerically for elevated temperatures. The main variables of the forming process include the fluid pressure, the pre-bulge pressure, and the process temperature. The effects of these parameters on the thickness distribution and uniformity index of the final product have been investigated. Using the hardness test, the preferred crystallographic orientation, the energy-dispersive spectroscopy, and the microstructure images obtained from an optical microscope and a scanning electron microscope, the relationship between the grain size, hardness, and effective plastic strain is studied and discussed. The findings imply that the HMDD process without the pre-bulge pressure reduces the uniformity of the final product and, on the other hand, excessive increase in this parameter causes tearing of the workpiece. The hardness distribution along the cup wall was in agreement with grain refinement and the Hall–Petch relationship, but it was not correspond to the expectations made via the texture analyses. The images gained from the energy-dispersive spectroscopy for different areas of the 2024 Al sample demonstrated that the Al2Cu precipitations in the product wall were finer than the other areas and mainly dispersed at the grain boundaries. This type of precipitation distribution was the main origin for increasing the hardness of the cup wall in comparison with the cup corner and bottom. In other words, the precipitation hardening overwhelmed the influence of the preferred orientation of the grains in HMDD operation of Al 2024.
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