Indian Journal of Science and Technology

Abstract

Objectives: To develop mathematical model for prediction of impact toughness of friction stir welded ZE-41 magnesium alloy joints. Methods/Analysis: Friction stir welded joints were fabricated using five different tool geometries. Total 31 experiments as dictated by central composite design technique with 4 factors, 5 levels were conducted. Model was developed using data obtained from this investigation. F-Test and Student’s t-test were conducted to investigate the adequacy of model. It was found that developed model is adequate. Findings: It can be concluded from the present research that taper cylindrical tool pin produced highest impact toughness as compared with other tool pins used. Threaded cylindrical pin yielded lowest impact toughness of the joint. It was further observed that welding speed have a profound effect on impact toughness. With increment in weld speed impact toughness increased to 4.5J then decreased with further increase in welding speed. Similar trend had been followed when tool rotational speed was varied. Micrographs of stir zone also support above results. Optimum parameters for obtaining maximum toughness had been presented. Application/Improvement: A novel mathematical model useful for prediction of impact toughness for improving the weld quality, commercially useful in aircraft, automotive and consumer electronic sectors. 

Keywords: Friction Stir Welding, Impact Toughness, Rare Earth, Response Surface Methodology, ZE-41 Magnesium Alloy