Effect of laser-arc offset and laser-deviation angle on the control of a Ti-Al interlayer

Abstract

Butt joining of an AA6061 aluminum alloy and a Ti-6Al-4V titanium alloy with a 3 mm thickness was carried out using laser-metal inert-gas hybrid welding-brazing without a bevel or an air gap. The uniformity of the interfacial intermetallic compound (IMC) layer was improved by changing the laser-arc offset and the laser-deviation angle. The weld appearance, IMC layer microstructure and tensile strength of the welded-brazed joints were investigated. A uniform serrated 1 μm thick TiAl3 layer was formed along the butt plane by using a laser-deviation angle. The tensile strength of the joint was closely related to the IMC layer morphology and thickness. Joints with excellent wetting and spreading on both sides achieved a maximum tensile strength of 230 MPa when the laser-arc offset was 1.2 mm and the laser-deviation angle was 5°. Three different fracture phenomena existed during the tensile test that correspond to different fracture positions at the interface layer, weld seam and heat-affected zone of the aluminum base metal.