Temperature-gradient joining of Ti-6Al-4V alloys by pulsed electric current sintering

The PECS method was used to join Ti-6Al-4V alloys. Temperature distribution in the samples during joining was analyzed by simulation and experimentally. Tensile strength of samples joined with or without graphite die were evaluated and compared. Similar experiments were also carried out in a hot-press (HP). Results indicated that the temperature at the contacting surfaces was the highest; good joints with high tensile strength (91.4% of matrix value) could be obtained at 700 C with a pressure of 5 MPa and a hold time of 5 min using the PECS method without the die. The microstructures of samples thus joined indicated that grains and phases grew across the interface between the two joined samples. Longer holding times, with higher joining temperatures and a higher pressure were needed to join the Ti-6Al-4V alloy by the HP method. Joint strength in this case did not exceed 57% of matrix value. (C) 2011 Elsevier B.V. All rights reserved.