Bainitic Transformations in Titanium Alloys

A large number of factors have an effect on the features and conditions of bainitic (intermediate) transformations in titanium alloys, namely: the type of phase diagram, the position of the eutectoid temperature, the eutectoid composition, the temperature of the start of martensitic transformation, and the rate of diffusion processes. This review provides a detailed analysis of the changes in these factors depending on the position of alloying metals in the periodic table of elements and highlights their influence on the course of bainitic transformations. The main reactions that influence the processes related to bainitic transformations are analyzed, and the main schemes of the formation of bainitic (intermediate) structures in titanium alloys are given. The crystallographic features of bainitic structures are considered, and a classification of intermetallic compounds that form in titanium alloys during the formation of bainitic structures is described. The review provides experimental data related to the features of the formation of bainitic (intermediate) structures in a broad class of titanium alloys with alloying metals belonging to Groups 5-11 of the periodic table of elements (Ti–V, Ti–Nb, Ti–Ta, Ti–Cr, Ti–Mo, Ti–W, Ti–Mn, Ti–Re, Ti–Fe, Ti–Ru, Ti–Os, Ti–Rh, Ti‒Co, Ti–Ni, Ti–Pd, Ti–Cu, Ti–Ag, and Ti–Au alloys).