Microstructures and Mechanical Properties of Additive Connecting Ti-6.5Al-2Zr-1Mo-1V Alloy by High Frequency Pulse TIG Technology

The TIG additive connecting technology has broad application prospects in manufacturing large complex titanium alloy components. The Ti-6.5Al-2Zr-1Mo-1V (TA15) alloy fabricated by HIP and CMT technology were connected by unpulsed and pulsed TIG additive connecting technology. The results showed that the macrostructure of fusion zone was epitaxial growth β columnar grains. The β columnar grains were significantly refined by pulse current. For unpulsed samples, fusion zone was mainly composed of α + β basketweave structure, with a small amount of lamellar α phase and acicular martensite α' phase. The lamellar α phase content in pulsed samples decrease compared with unpulsed samples. The average values of UTS, YS and EL of the pulsed samples were 1038 MPa, 965 MPa and 9.52%, respectively. Compared with the unpulsed samples, it increased by 2.1%, 3.7% and 43.6%, respectively. The fracture mode of the unpulsed and pulsed samples was the combination of ductile fracture and brittle fracture.