Effect of intermetallic compounds on heat resistance of hot roll bonded titanium alloy-stainless steel transition joint

The effect of intermetallic compounds on the heat resistance of transition joint was investigated. The experiment of post-weld heat treatment for the hot roll bonded titanium alloy stainless steel joint using nickels interlayer was carried out, and the interface microstructure evolution due to heat treatment was presented. There was not found significant interdiffusion at stainless steel/nickel interface, when the specimens were heat treated in the temperature range of 600-800 degrees C for 10 and 30 min, while micro-cracks occurred at the stainless steel/nickel interface heat treated at 700 degrees C for 30 min. The thickness of intermetallic layers at nickel/titanium alloy interface increased at 600 degrees C, and micro-cracks occurred at 700 and 800 degrees C. The micro-cracks occurred between intermetallic layers or between intermetallic layer and nickel interlayer as well. The tensile strength of the transition joint decreased with the increase of heat treatment temperature or holding time.