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چکیده
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Herein, the effect of post-weld heat treatment on the tensile properties of friction stir-welded (FSW) joints of nano/ ultrafine-grained (NG/UFG) AA2024 alloy sheets produced by accumulative roll bonding (ARB) was investigated. Continuous and discontinuous dynamic recrystallizations were the main mechanisms of microstructure evolution in the stir zone of joints. As a result of recrystallization and larger grain sizes achieved during FSW, the ARB followed by FSW improved ductility and strain hardening. The ARB specimens had yield strength, tensile strength, and elongation values of 265 MPa, 450 MPa, and 7 %, respectively. FSW-welded ARB specimens showed yield strength, tensile strength, and elongation of 230 MPa, 440 MPa, and 11 %, respectively. After T6 treatment, there was an increase in tensile and yield strength of 550 and 310 MPa, respectively, due to the Orowan looping mechanism, which reduced the elongation of the specimen. In conclusion, FSW was suggested as a method of joining the NG/UFG AA2024 alloy sheets while highly retaining the refined microstructure.
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