Quantitative microstructural characterization of a near beta Ti alloy, Ti-5553 under different processing conditions

Ti-5553 (Ti–5Al–5Mo–5V–3Cr) is a near beta Ti alloy with potential applications in structural components of aircrafts. In near beta Ti alloys, microstructural features can be varied over a wide range of length scales by changing different heat treatment parameters. Quantitative characterization of different microstructural features of each of those differently heat treated material is of considerable importance to eventually develop a model relating quantitatively, processing, microstructure and mechanical properties. In the present work, quantitative microstructure characterization, using stereological methods, has been performed on various microstructures developed through variations in separate heat treatment variables, as well as variation in each of the different individual variables of a set of sequential combined thermo-mechanical processing steps to obtain beta annealed microstructure. Quantitative effect of processing on microstructure is discussed and a TTT diagram is constructed for alpha precipitation in Ti-5553 alloy.