Material flow pattern in friction stir welding of AZ31 magnesium alloy

A thin Cu coating was deposited on both sides of AZ31 magnesium alloy to be joined to study the material flow in friction stir welding.The results show that the probe wipes the material from the advancing side into a rotating and moving zone,and material rotates,advances,and descends helically in the stir zone and rises in the outer part of the rotating zone.