Multi-criteria optimization on friction stir welding of aluminum composite (AA5052-H32/B4C) using titanium nitride coated tool

Abstract The boron carbide (B4C) reinforced AA5052-H32 aluminium composite has been initially fabricated by stir casting method. Friction stir welding (FSW) is used to join two similar AA5052-H32/B4C plates using a titanium nitride (TiN)-coated square tool. The tool wear loss, microhardness, and tensile strength of FSW joints have been investigated by the Taguchi technique. Welding parameters consist of TiN coating thickness, tool rotational speed, welding speed, and axial thrust. Taguchi analysis is used to determine the influences, contributions, and best values of welding parameters to meet optimal welding attributes. The maximum tensile strength (140.134 MPa) has been obtained by increasing the TiN coating thickness, tool’s rotational speed, axial thrust, and welding speed. At the highest tool speed and axial trust, the maximum microhardness (158.3 HV) has been attained. The minimum tool wear loss (9.023%) has been obtained by welding at a moderate speed with maximum rotational speed, axial thrust, and TiN coating thickness. Fractography and SEM analysis have been used to analyze the microstructural behaviour of welded aluminium composite materials and worn-out tool surfaces. The Additive Ratio Assessment (ARAS) multi-criteria optimization technique has been applied to predict the best welding parameters to attain the optimal welding characteristics. The 40 μm TiN coating thickness, 1200 rpm tool rotation, 20 mm min−1 welding speed, and 6000N axial force are predicted to achieve 108.6 MPa tensile strength, 110 HV microhardness, and 9.37% tool wear loss.