Thesis Type: Postgraduate
Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2022
Thesis Language: Turkish
Student: BAŞARAN BEKİR BAŞPINAR
Supervisor: Mehmet Fatih AycanAbstract:
The CAF process is one of the advanced manufacturing methods in which panels with largescale complex geometries can be produced in the aerospace industry and integrated structures, also known as integrated panels, which are frequently used in military aviation applications. The aging heat treatment and the shaping process are carried out simultaneously in a hybrid manner. In the process carried out under elastic loading, the formation of plastic deformation is possible by stress relaxation, which occurs as a result of keeping the workpiece limited by the mold contour under a constant strain from the beginning to the end of the process. In the process where high springback rates occur, the most critical step in the production phase is to know the springback rate and to design the mold accordingly. In this study, the springback behavior of 2024 T3 aluminum alloy at different sheet thickness and different pressure values in the case of simultaneous shaping while aging to T81 temper by CAF process was experimentally investigated. Within the scope of the study, 2024 T3 sheet materials with a thickness of 0,810, 1,016, 1,270 and 1,600 mm, which are widely used in aviation, were preferred. The temperature and time information required for aging an alloy in 2024 T3 temper to T81 have been determined according to AMS2770. For this reason, all samples were subjected to creep aging shaping process at 190 °C for 12 hours. The samples were shaped under pressure of 0,6, 0,7, 0,8 and 0,9 MPa. It has been experimentally observed that when the parameters such as mold geometry, part dimensions, process time and temperature are kept constant, the springback rate decreases when the material thickness increases, and likewise, the springback rate decreases with the increase of the forming pressure while the other parameters are constant.
Key Words : Creep age forming, AA2024, Stress relaxation, Aging heat treatment,