Laser pressure welding of AZ31 magnesium and A6061 aluminum

Abstract

Experimental tests of a laser pressure welding were carried out for joining dissimilar metals. In this method, a 2 kW YAG laser beam was irradiated into a wedge-shaped-gap by a f:θ lens and scanned at various frequencies and patterns using two dimensional scanning mirrors. Then the sheets were pressed by the pressure rolls to be joined.In the tests, AZ31 magnesium and A6061 aluminum alloy sheets were used. The laser pressure welding was carried out at various laser powers, scanning speeds of the laser beam and travelling speeds of the welded sheets. The intermetallic compounds were observed and analyzed by SEM and EDX, and the layer thicknesses were measured. When the scanning speed increased from 30 Hz to 75 Hz, the layer thickness decreased from 5.0 µm to 1.0 µm at the travelling speed of 0.5 m/min. However, it was almost the same thickness as 1.0-1.5 µm over the used scanning speeds when the travelling speed was set at 0.3 m/min. The strength of the welded sheets was evaluated by the tensile shear test. When the scanning speed increased from 30 Hz to 75 Hz, the shear strength increased from 14.8 MPa to 19.8 MPa at the travelling speed of 0.5 m/min. On the other hand, at the scanning speed of 30-60 Hz at 0.3 m/min, the specimen fracture occurred in a parent sheet of A6061 aluminum alloy side.Experimental tests of a laser pressure welding were carried out for joining dissimilar metals. In this method, a 2 kW YAG laser beam was irradiated into a wedge-shaped-gap by a f:θ lens and scanned at various frequencies and patterns using two dimensional scanning mirrors. Then the sheets were pressed by the pressure rolls to be joined.In the tests, AZ31 magnesium and A6061 aluminum alloy sheets were used. The laser pressure welding was carried out at various laser powers, scanning speeds of the laser beam and travelling speeds of the welded sheets. The intermetallic compounds were observed and analyzed by SEM and EDX, and the layer thicknesses were measured. When the scanning speed increased from 30 Hz to 75 Hz, the layer thickness decreased from 5.0 µm to 1.0 µm at the travelling speed of 0.5 m/min. However, it was almost the same thickness as 1.0-1.5 µm over the used scanning speeds when the travelling speed was set at 0.3 m/min. The strength of the welded sheets was evaluated by the tensile shear test...