抄録
The feasibility of fabricating butt joints made of dissimilar materials thixomolded magnesium alloy AZ91D and titanium, by friction stir welding method (FSW) was studied. AZ91D and titanium plates of 2mm in thickness were butt-joined FSW according to different joining parameters for probe position and axial tool loads. A probe was inserted at the AZ91D side and the probe edge was slightly offset from the joint interface into the titanium side by up to 0.5mm. AZ91D plates were positioned at the advancing side and the titanium was positioned at the retreating side, respectively.
The tensile strength of the joint increased with increasing probe distance from the joint interface into the titanium side. Maximum tensile strength reached 226MPa at axial tool load of 7.8kN and probe position of 0.5mm into the titanium side. The joint efficiency was at least more than 95%. At the joint interface, intermetallic compound of titanium and aluminum was not found under a scanning electron microscope, but a rich aluminum layer was seen formed near the interface of the AZ91D and titanium.
