Microstructures and mechanical properties of friction welded joint using a 5052 aluminum alloy small diameter rod

5052-H34 aluminum alloy with 5 mm in diameter was friction welded using a conventional automatic friction welder. The effect of welding conditions on microstructures and mechanical properties of friction welded joints were investigated. Total loss of welded joints increases with increasing both the rotational speed and friction time. In addition, the total loss was negligibly low when the welding condition was N=6000 rpm and t1=1 s. Macrostructures of welded joints showed symmetrical structure with respect to the weld interface and the rotational axis. A layer with fine-grained microstructure was formed at the weld interface. The layer grew thicker by increasing both rotational speed and friction time. Heat affected zone was formed around the fine-grained layer. It tends to increase with increase of both the rotational speed and friction time. The softened area of the joints reached to about 8 mm from the weld interface. In addition, weld interface was cured under conditions of N=6000 rpm and t1=1 s.The highest tensile strength of thin diameter joints was 209 MPa, which was obtained under the condition of N=6000 rpm and t1=3 s. Its joint efficiency reaches 80% of the base metal. © 2015 The Japan Institute of Light Metals.