Experimental investigation on the improvement of the properties of the AZ80A Mg alloy joints using friction stir welding process

Abstract

An experimental investigation was conducted with the basic objective of demonstrating the feasibility of joining the AZ80A Mg alloys using the technique of friction stir welding (FSW). Good quality joints free from defects were obtained for 5mm thickness AZ80A Mg alloy flat plates at a speed of rotation of 750 rpm with a traversing speed of 1.5 mm/min, by employing a FSW tool fabricated out of M35 grade High Speed Steel(HSS). It was experimentally observed that, the nugget zone (NZ) of the defect free weldments were found with fine sized, equally spaced & uniformly distributed grains when compared with that of the parent metal. Apart from this, the heat affected zone (HAZ) lying beside the NZ was found to possess larger sized near equaxied grains due to the effect of annealing. The weld zones were found to possess regions of slight softening nature when compared to that of the parent metal, arising from the dislocation of the lower densities. Moreover, the tensile strength of the defect free weldments was found to be around 78% of the parent metal, which seems to better than that of the strengths obtained using conventional joining techniques.

Keywords

• friction stir welding
• az80a mg alloy
• joint properties
• tensile strength
• traversing speed
• tool rotational speed
• nugget zone
• heat affected zone