Abstract:The high vacuum electron beam isolation welding (EBIW) was used to join vanadium alloy (V-5Cr-5Ti) to stainless-steel (HR-2) with different electroplated metal coatings. To investigate the effects of electroplated coating (Au, Ag, Cr and Ni) on the weldability, the weld appearance, the microstructure and the mechanical properties of the joints have been analyzed. The results show that the metallurgically bonded joints of V-5Cr-5Ti/Au(Ag, Cr, Ni)/HR-2 are achieved with EB off-set. The welds surface configuration are good and root reinforcement are full and smooth. The integration interface of V-5Cr-5Ti and fusion zone (FZ) is relatively flat, where an electroplated metal enrichment zone is found near V alloy side. The FZ consists of considerably smaller equiaxed dendritic structure in the center and columnar dendritic grained at the fusion line between FZ and HR-2. Au and Ag exhibit good isolation layer which helps increasing the weld quality. The maximal tensile strength of V-5Cr-5Ti/Au(Ag)/HR-2 of EBIW joint is over 400 MPa. There is no crack and detected porosity in the joints through X-ray inspection. In contrast, the tensile strength of V-5Cr-5Ti/Cr(Ni)/HR-2 of EBIW joints are lower than 100 MPa