Alloys of the Ti-Si-Sn system (titanium corner): phase equilibria, structure, and mechanical properties

Abstract

The joint effect of Si (5, 7, and 10 at.%) and Sn (3–15 at.%) on the structure and mechanical properties of Ti-rich as-cast Ti–Si–Sn alloys is studied. Hypoeutectic alloys with 10 at.% Si are shown to possess the highest level of properties due to a greater volume fraction of the (β*) + Ti 5 Si 3 . eutectic. It is shown that the dependence of strength and hardness of Ti–Si–Sn alloys on Sn content is nonmonotonic. The properties improve with increasing tin content to 7–10 at.% due to the solidsolution hardening mechanism. The elastic modulus and plasticity of all the alloys decrease with increasing Sn content. The elastic modulus for the alloys with 7–15 at.% Sn almost halves, decreasing to 65–60 GPa. The level of long-term hot hardness of the alloys at different temperatures depends on Si and Sn content. In general, tin additions increase heat resistance of all the alloys studied. The deviation from the dependence for individual alloys results from variation in their phase composition. The mechanical behavior of Ti-rich Ti–Si–Sn alloys depending on Sn content is determined by the formation of the intermetallic Ti 3 Sn phase.