Optimization of Hybrid Friction Stir Welding Process Parameters of Aluminium AA6063

Abstract

The present work aims to develop an ultrasonic assisted friction stir welding (UAFSW) setup to enhance the quality of welds attained. Experiments have been conducted on AA6063 Aluminium plate of dimension 200mm x 80mm x 3mm as per Taguchi methodology. Optimization of process parameters such as rotational speed, traverse speed, axial load and amplitude of vibration have been done using L9 orthogonal array for responses such as surface roughness, tensile strength and microhardness of weld bead. It has been observed that the contribution to surface roughness by ultrasonic vibration was 2.14% whereas that of tool rotational speed was 64.32%, a major contribution. The maximum tensile strength is attained at high rotational speed, traverse speed and axial load, and minimum amplitude of vibrations. Maximum value of microhardness is observed in the centre of weld bead. Microstructural investigation has been done on the samples with the use of scanning electron microscope. It is observed that larger grain size is found in UAFSW as compared to conventional FSW. Cavity defect and improper mixing of the materials are observed in UAFSW.