Cold metal transfer welding-brazing of pure titanium TA2 to magnesium alloy AZ31B

Abstract

Pure titanium TA2 was joined to Mg AZ31B by cold metal transfer (CMT) welding-brazing method in the form of two lap-shear joints (Mg-Ti joint and Ti-Mg joint) with Mg AZ61 wire. The microstructure of Ti/Mg CMT joints was identified and characterized by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The mechanical properties of various welding parameters were compared and analyzed. Desired Ti/Mg CMT joints with satisfied weld appearances and mechanical properties were achieved at suitable welding variables. The Ti/Mg CMT joints had dual characteristics of a welding joint at the Mg side and a brazing joint at the Ti side. Moreover, for two joints, the brazing interfaces were composed of an intermetallic compounds (IMCs) layer including Ti 3Al, Mg17Al12 and Mg0.97Zn 0.03 phases. Mg-Ti joint had the higher tensile load of 2.10 kN, and Ti-Mg joint had the tensile load of 1.83 kN. © 2014 Elsevier B.V. All rights reserved.