Improving the mechanical properties of friction stir welded AZ31B magnesium alloy flat plates through axial force investigation

In this paper, the effects of axial force on the mechanical properties of AZ31B magnesium alloy flat plates during the Friction Stir Welding (FSW) process were investigated by carrying out the tensile tests as per the American Society for Testing and Materials (ASTM) E8M-11 standards. The tensile test results indicated that the increase of the axial force greatly improved the tensile shear load (TSL) of the friction stir welded joints at a constant tool rotational speed of 800 rpm and welding speed of 50mm/min. Sound lap joints with low distortion, lack of cavity and high tensile strength were successfully obtained with an axial force of 5kN. However, the TSL of the friction stir welded joints decreased when the axial forces were 3kN and 4kN with the same constant tool rotational and welding speed.