Multi-objective optimization of FSW process parameters for AA1100 joints by using a hybrid technique of PCA-TOPSIS

The friction stir welding (FSW) process is generally preferred to join aluminium and its alloys to facilitate effective joining with better strength and lesser defects. In the present work, application of full-factorial experimental design in combination with principal component analysis (PCA) and Technique for order of preference by similarity to ideal solution (TOPSIS) have been adopted to evaluate the effectiveness of optimizing multiple performance characteristics for joining 5 mm thick AA1100 plates by FSW technique with a square pin tool. The effect of process parameters such as tool rotational speed, welding speed and plunge depth on the response variables that are ultimate tensile strength, flexural stress, microhardness, average grain size and residual stresses has been studied. The optimal parameter setting is achieved at rotational speed = 1200 r min⁻¹, welding speed = 40 mm min⁻¹ and plunge depth = 0.3 mm. Predicted results have been verified by confirmatory tests which show an improvement of 1.45 Mpa increase in tensile strength of the weld sample. This procedure can be advantageous for various industries and researchers as an optimum condition for multiples responses is very essential for manufacturing processes in the current scenario.