Friction Stir Welding Experiments on AZ31B Alloy to Analyse Mechanical Properties and Optimize Process Variables by TOPSIS Method

The present work involves friction stir welding of AZ31B magnesium alloy plates by using copper as tool pin material. The friction stir welding input factors namely tool pin profile, tool rotational speed, tool feed and tool angle were varied to find their influence on the quality of the processed zone. For mechanical and micro structural study of the processed specimens, tensile test, hardness test and microscopy tests were carried out. The Taguchi\u27s experimental combination of L18 mixed orthogonal array has been utilized for conducting experiments. ANOVA was utilized to evaluate the influence of each input factor on the response measures. TOPSIS, the multi-response optimization technique was applied to obtain the optimal setting for getting enhanced results. The experimental results of the optimum set provided a tensile strength of 206.35 MPa, Percentage elongation of 7.4% and Vickers hardness of 68 which are 88.2%, 52.9% and 79% of the corresponding property values of the base material respectively. Microstructural study revealed the refinement of grains in the processed zone. However the enhancement of properties is prevented by the occurrence of defects