Improving the Mechanical Properties of Aluminum Alloys 6061-T6 Friction Stir Welding Joints Using Ultrasonic Peening

Abstract

The aim of this paper is to study the possibility of joining plates from aluminum alloy 6061-T6 by friction stir welding method. Plates were prepared to dimensions (200 × 60 × 6) mm by using (CNC) milling machines. The FSW was then applied to join the operated plates by a vertical milling machine using different rotation welding speed of 1000,1200,1400, rpm and linear welding speed of 30 mm/min for the production of many weld joints. Microstructure and micro hardness, tensile, bending, temperature distribution testing were implemented. The results observed that the effect of the increasing of rotating speed for friction stir welding leads to increase the mechanical properties due to the increase of heat input. The best result was obtained at rotational speeds (1400) rpm, the specimens that are welded at 1000 rpm and had decreases in mechanical properties are subjected to ultrasonic peened surface treatment at 1,2,3 passes to improve the mechanical properties of welded joint, Compared to the non-peening weld joint, the mechanical properties increased when the number of ultrasonic peened passes increased due to the surface hardening and compressive residual stresses produced by the ultrasonic peening process.