Abstract： Using original solder as filler composite, the arcultrasonic was motivated by modulating TIG arc at high frequency.The effects of arcultrasonic on pore distribution,microstructure and mechanical properties of MGH956 alloy joints produced by arcultrasonic TIG welding with different excitation current were investigated. The results show that the size of pores changes markedly with the increasing of excitation current，while the number decreases slightly. Arcultrasonic can break or reduce the growth of coarse columnar grain near the weld interface. The refined grains can be achieved by arcultrasonic in welding process with better effect for increased excitation current in a certain range.When the excitation current reaches 30 A，the grains are coarsened by high heat input. The maximum tensile strength of welding joint is 623 MPa with 23 A arcultrasonic，which is 86.5% of base metal strength.
2013, Vol. 34 
