Research Article CharacterizationoftheRoleofSqueezeCastingonthe MicrostructureandMechanicalPropertiesoftheT6HeatTreated 2017AAluminumAlloy S.Souissi , 1 N.Souissi, 2 H.Barhoumi, 2 M.benAmar, 1 C.Bradai, 1 andF.Elhalouani 1 1 Laboratory LASEM, National Engineering School of Sfax (ENIS), University of Sfax, B.P. 1173-3038 Sfax, Tunisia 2 Faculty of Sciences of Sfax, University of Sfax, Sfax, Tunisia Correspondence should be addressed to S. Souissi; slim.souissi@ymail.com Received 29 October 2018; Accepted 24 December 2018; Published 22 January 2019 Academic Editor: Pavel Lejcek Copyright © 2019 S. Souissi et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In this study, the effects of squeeze casting process and T6 heat treatment on the microstructure and mechanical properties of 2017A aluminum alloy were investigated with scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), differential scanning calorimetry (DSC), and microhardness and tensile tests. e results showed that this alloy contained α matrix, θ-Al 2 Cu, and other phases. Furthermore, the applied pressure and heat treatment refines the microstructure and improve the ultimate tensile strength (UTS) to 296 MPa and the microhardness to 106 HV with the pressure 90 MPa after ageing at 180 ° C for 6 h. With ageing temperature increasing to 320 ° C for 6 h, the strength of the alloy declines slightly to 27 MPa. en, the yield strength drops quickly when temperature reaches over 320 ° C. e high strength of the alloy in peak-aged condition is caused by a considerable amount of θ′ precipitates. e growth of θ′ precipitates and the generation of θ phase lead to a rapid drop of the strength when temperature is over 180 ° C. 1.Introduction Due to their excellent mechanical and physical properties, Al-Cu cast alloys are used in automobile and military in- dustries, aerospace, and in applications such as floor beams, engine pistons, wing box, covers, brake components, fuel tanks, slot tracks wheel, fittings, fuel systems, body skin connectors [1–3]. However, the major problems in casting these alloys consist in their high tendency to form casting defects such as hot tearing, solidification shrinkage, porosity [2], and their bad fluidity in conventional casting processes. ese problems have negative effects on the mechanical properties and have greatly limited the application of Al-Cu cast alloys. Nowadays, for improved alloy properties, the microstructure refinement of Al-Cu cast alloys has become an important research field because mechanical properties can be sig- nificantly enhanced by microstructure refinement. Squeeze casting is one of the modern casting processes which have been invented to address these imperfections and has a high potential to produce sound castings. It is a metal-forming process which combines permanent mould casting with die forging into a single operation where molten metal is solidified under applied hydrostatic pressure [4–6]. e process, which is suitable for shaping both cast and wrought alloys, improves product quality by pressurized solidification, which prevents the formation of shrinkage defects, retains dissolved gases in solution until freezing has completed, and has the priority to form the equiaxed grain structure [7, 8]. Many research works on the advantages of squeeze casting process have been discussed. Souissi et al. [9] have shown that squeeze casting caused the refinement of the microstructure and reduction in the dendrite arm spacing (DAS) of the cast structure possibly due to in- creasing the cooling rate of 2017A aluminum alloy. ey found that the gravity cast specimens have the lowest UTS compared with the squeeze cast specimens. However, the increase of UTS and YS is obvious at the 50MPa and 100 MPa pressure. In the same way, Souissi et al. [10] have studied Al-13% Si alloy and found that the dendrite size of Hindawi Advances in Materials Science and Engineering Volume 2019, Article ID 4089537, 9 pages https://doi.org/10.1155/2019/4089537