Mechanical efficiency in the friction stirwelding of magnesium alloy AZ31B

Abstract

The aim of the present work was to determine the relationship between the microstructures and the resultant mechanical properties in the Friction stir welded joints of the Mg alloys AZ31B, as a function of the main process variables, implemented from the use of a conditioned universal milling machine. Sound welds without defects, with corresponding high values of mechanical strength, were obtained for different levels of the ratio rotationspeed /welding speed of the welded joints, with the maximum mechanical efficiency obtained of 93%. Themicrostructural characterization in the stirred zone showed fine equiaxed homogeneous grains with an averagediameter of 10 μm. The failure of tension specimens occurred generally trough the advancing side, showing a surfacemorphology ductile-like with a low plastic deformation of less than 5%. Quality and mechanical results of FSWedjoints of Mg alloy AZ31B, let us to assure the convenience of using them for structural applications taking into account their high specific mechanical strength.