Microstructure of titanium alloy in additive/subtractive hybrid manufacturing: a review

Due to its exceptional characteristics, including high-temperature resistance, corrosion resistance, and oxidation resistance, titanium alloy is extensively utilized in advanced fields such as aerospace and biomedical applications. Additive/Subtractive Hybrid Manufacturing (A/SHM) combines the advantages of Additive Manufacturing (AM) and Subtractive Manufacturing (SM), facilitating the one-step fabrication of complex component structures with high precision and quality. This approach offers innovative design concepts and methodologies for the processing and manufacturing of titanium alloy components. This review recapitulates the evolution laws of microstructure formation of titanium alloys in A/SHM, including phase composition and grain morphology, and expounds the correlation between microstructure and mechanical properties. It encompasses the influence of different processes such as scanning speed and laser power in A/SHM on the microstructure of titanium alloys and conducts process optimization. It further analyzes the deficiencies and challenges in the current cognition of A/SHM and presents personal insights into future research directions. This review also introduces the industrial applications of titanium alloy components fabricated by A/SHM and emphasizes its extensive development potential.