Influence of heat treatments on corrosion behavior of Ti64 friction welds

In this present investigation, rotary friction welding has been used to join Ti64 rods. Different heat treatments namely α-β and β with stress-relieving (SR) were carried out before welding. After welding, corrosion studies were carried out in a 3.5% NaCl environment. It was observed that the α-β heat-treated condition with SR showed the least corrosion rate out of all conditions, whereas the β heat-treated condition has shown the highest. The primary reason for this is the microstructural changes due to heat treatment. Below β transus temperature led to the development of uniform α-β lamellar colonies around the primary α which provided good corrosion resistance in α-β heat-treated condition with SR. The above β transus heat treatment led to evolving fully lamellar structure which made the corrosion rate high. The optimized results indicate that the α-β followed by SR before welding has a better overall performance in corrosion resistance.