Investigation of the Effect of Tool Temperature on Microstructure, Hardness, and Wear Behaviour of Aluminium 6061-T6 Alloy Welded by the Friction Stir Welding Process

Abstract

The friction stir welding (FSW) tool is a critical component to the success of the welding process. The aim of the paper is to investigate the effect of tool temperature on the microstructure and mechanical properties of the aluminium alloy during the friction stir welding process. The welding experiment was conducted at a tool rotational speed of 550 rpm, and tool temperature was measured with the increment of a 60 mm distance. Three different tool temperatures were obtained, and samples were characterised by scanning electron microscopy (SEM). The ASTM E384 standard was followed when conducting the Vickers hardness test, and material wear behaviour was tested using the ASTM G99 tribology testing standard. The results show that the tool temperature increases with distance during the FSW process (40.5, 46, and 54°C). A high tool temperature produces the weld butt with high mechanical properties (87.5 HV). The wear rate is low at a high tool temperature ( $1.169E-006$  mm3/N/m).