Objective Titanium alloy is a new material used in rail vehicle manufacturing, featuring excellent corrosion resistance, weldability, high specific strength, and a lower density than carbon steel. These properties meet the development requirements of vehicle lightweighting and adaptation to complex service environments. Currently, researches on the metallurgical phase transformation and corrosion resistance of titanium alloys remain insufficient. Therefore, it is necessary to study the influence of annealing processes on the microstructure and corrosion behaviors of titanium alloys.

Method The TC4 titanium alloy with varying phase microstructures is investigated under different annealing temperatures and durations. The phase fraction and size of the TC4 titanium alloy with different microstructures are obtained using XRD (X-ray diffraction) and SEM (scanning electron microscopy). The corrosion resistance of the TC4 titanium alloy with different microstructures is eva-luated through electrochemical and immersion tests. The mass fraction of each element in the TC4 titanium alloy before and after corrosion is detected via SEM.

Result & Conclusion After different annealing treatments, the corrosion resistance of TC4 titanium alloy is found to be directly proportional to the mass fraction of the α phase and inversely proportional to the phase size. Aluminum (Al) element is a crucial factor influen-cing the corrosion resistance of TC4 titanium alloy. Reducing its elemental segregation can decrease the corrosion rate and improve the corrosion performance of the titanium alloy.