Microstructure And Mechanical Property Of TIG Welded Joints Of Titanium Alloy/Stainless Steel

TIG welding of titanium alloy (TC4) and stainless steel (1Cr18Ni9Ti) was investigated in this paper, using Cu, CuNi alloy and Nb as filler metals. The tensile strength was examined by electronic testing machine, and welded joints were analyzed by optical microscope, SEM, EDAX and XRD.Experimental results show that the microstructure of welded joints of stainless steel is homogeneous, and the tensile strength is up to 526MPa, using CuNi alloy as filler metal. The chemical composition of welded joints of titanium alloy is homogeneous, and the tensile strength is up to 520MPa, using Nb as filler metal, and it is higher than Cu or CuNi alloy as filler metals. The fracture path occurred in welded joints, and it is belongs to ductile.It is difficult to avoid the intermetallics during welding titanium alloy and stainless steel, using Cu, CuNi alloy and Nb as filler metals, respectively. The microstructure of welded joints between titanium alloy and stainless steel is intricate, and the tensile strength is up to 125MPa, using CuNi alloy as filler metal, and it is higher than Cu or Nb as filler metals.The intermetallics could be avoided effectively by using the method of transition layers between titanium alloy and stainless steel, and the tensile strength of welded joints is enhanced. The tensile strength of welded joints is up to 210MPa, using Nb and Cu as filler metals together, The fracture path occurred between Nb layer and Cu layer. And compared to others, the microstructure of this welded joints is homogeneous.