Predicting tensile strength, hardness and corrosion rate of friction stir welded AA6061-T6 aluminium alloy joints

AA6061-T6 aluminium alloy (Al–Mg–Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring high strength-to-weight ratio and good corrosion resistance. The friction stir welding (FSW) process and tool parameters play major role in deciding the joint characteristics. In this research, the tensile strength and hardness along with the corrosion rate of friction-stir-butt welded joints of AA6061-T6 aluminium alloy were investigated. The relationships between the FSW parameters (rotational speed, welding speed, axial force, shoulder diameter, pin diameter and tool hardness) and the responses (tensile strength, hardness and corrosion rate) were established. The optimal welding conditions to maximize the tensile strength and minimize the corrosion rate were identified and reported here.

Research highlights
► Multi objective optimization using response surface methodology (RSM) is an useful technique to optimize the FSW process and tool parameters.
► Developed empirical relationships is useful to relate the FSW input parameters and the output responses.
► Finding the optimal welding combination that would maximize both the tensile strength and hardness with minimum corrosion rate.