High temperature oxidation and hot corrosion behavior of laser additive manufactured TiAl4822/TC25G graded materials at 750 °C

Abstract

Laser additive manufacturing of titanium-based graded materials offers a promising route to enhance the performance of aero-engine compressors. However, the high temperature corrosion behavior of these materials remains difficult to predict due to compositional variations across different regions of the graded structure. This study investigates the high temperature oxidation and hot corrosion behaviors of laser additively manufactured TiAl4822/TC25G graded materials at 750 °C. The results show that the mass gain after hot corrosion is markedly higher than that after high temperature oxidation, which is attributed to accelerated corrosion damage induced by the presence of mixed salts. As the graded material transitions from the TiAl4822 alloy region to the TC25G alloy region, the Al 2 O 3 content in the high temperature oxidation layer decreases, leading to a gradual degradation of oxidation resistance. Concurrently, the hot corrosion product layer becomes progressively thicker and more porous, accompanied by internal corrosion, resulting in a decline in hot corrosion resistance. Furthermore, different regions of the graded material exhibit distinct internal corrosion characteristics, and the corrosion susceptibility varies among different phases.