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

Abstract

The present paper is aimed to study the microstructural and mechanical characteristics of friction stir welded AA5083-H112 aluminium alloy butt joints fabricated by inserting AA2024-O aluminium alloy thin plate. In this research, a thin AA2024-O foil with the size of 2 mm x 3 mm x 300 mm was inserted between the faying surfaces of two AA5083-H112 plates to be joined. Friction stir welding (FSW) process was conducted using a 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 with and without inserted materials 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 the conventional FSW joints (220,8 MPa). Similarly, the weld nugget zone (WNZ) fabricated using inserted materials have high hardness compared to that produced by conventional FSW. The improved mechanical properties of the FSW joints with inserted AA2024-O materials could be related to the occurrence of diffusion from the inserted material into AA5083-H112 plates combined with precipitation hardening.