CORROSION RESISTANCE AND MECHANICAL PROPERTIES OF TITANIUM-STAINLESS STEEL JOINTS BONDED BY AI, Cu AND Ni INTERLAYER

The purpose of this study is to compare the dissimilar joints of pure titanium to stainless steel achieved by different intermediate materials like aluminum, copper and nickel. Due to the metallurgical incompatibility between those base materials, it has been very difficult to produce reliable joints due to the formation of FeTi and Fe2Ti intermetallic compounds. The purpose of using the intermediate material is to reduce and even block the diffusion between titanium and stainless steel. The thickness of those filler metals were 100 pm. The microstructure of the joints were investigated using scanning electron microscopy equipped with an energy dispersive X-ray system (EDS) to determine chemical composition of joint. The maximum values of tensile strengths were obtained for samples prepared using copper as a interlayer. The highest impact energy was achieved for joints performed using aluminum as a filler metal. SEM characterization of the fracture surfaces of the joints shows that the character of fractures are brittle for the samples achieved by copper, nickel and quasi brittle for the specimen prepared using aluminum. The galvanic corrosion test was carried out in a 3.5 % NaCI solution. The potentiodynamic polarization curves show that the higher corrosion potential as well as a lower corrosion current were registered for the joints performed by nickel.