Interfacial intermetallic compounds formation at interface for joining selective laser melted and wrought Ti6Al4V alloy

Taking advantage of both selective laser melted and wrought samples, joining them together is extremely interesting. In this study, specimens of selective laser melted and wrought Ti6Al4V alloy were diffusion bonded using Cu interlayer, as a first attempt, to evaluate the influence of bonding parameters on microstructural developments and the performance of joints. The diffusion bonding was accomplished using a simply designed fixture, with the industrial applicability, at 820, 850 and 870 °C, with a holding time of 2 h. Obtained joints were studied by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), X-ray diffractometry (XRD), micro-hardness measurement and shear strength test. The observation of microstructures showed that sound joints comprising several intermetallics can be formed by this method. The shear strength of about 125 MPa was obtained during bonding at 850 °C, in which diffusion layers comprising several intermetallic compounds - Ti₂Cu, TiCu, Ti₃Cu₄ and TiCu₂ - were detected inside the interface of joints.