Influence of AA2024-O inserted material on microstructure and mechanical properties of FSWed AA5083-H112 joints

The present paper is aimed to study microstructure and mechanical properties of friction stir welded (FSWed) AA5083-H112 aluminum alloy butt joints fabricated by inserting AA2024-O aluminum alloy thin foil. In this research, a thin AA2024-O foil with the size of 2 x 3 x 300 mm3 was inserted between the faying surfaces of two AA5083-H112 plates to be joined. FSW process was conducted using tool rotational speed of 1500 rpm, tool traveling speed of 30 mm/minute, and tool tilt angle of 2o. After welding, microstructural, hardness, and tensile properties of the FSWed joints without and with inserted AA2024-O thin foil were compared. Results showed that FSWed joints with inserted AA2024-O material have an ultimate tensile strength (UTS) of 249.8 MPa which was higher than that of conventional FSW joints (220.8 MPa). Similarly, the weld nugget zone (WNZ) fabricated using the inserted material has higher hardness compared to that produced by conventional FSW. The improved mechanical properties of the FSW joints having inserted AA2024-O material could be related to the occurrence of diffusion from the inserted material into AA5083-H112 plates combined with precipitation hardening.