Parametric optimization of AA6061-Cu friction stir welded joints with boron carbide particle reinforcement.

The objective of this work is to improve the mechanical properties of friction stir welded square butt joints of AA6061 and pure copper employing activated flux of B₄C micro powder. Rotational speed, transverse feed and tool penetration depth were optimized using Taguchi method to produce joints devoid of defects. Rotational speed was found to be the most influential process parameter in achieving the higher ultimate tensile strength and has 49% contribution followed by feed and penetration depth. Model predictions for the optimal strength were validated and found to have 5 % variation. Highest ultimate tensile strength and micro Vickers hardness of 259.57 MPa and 98.58 HV respectively were obtained for joints made with speed, feed and penetration depth of 1250 rpm, 20 mm/min and 0.1 mm respectively. The microstructural analysis revealed that B₄C particles were distributed uniformly in the stir zone which could be the reason for improved mechanical properties. [ABSTRACT FROM AUTHOR]