Effect of Silicon Addition on Microstructure and Mechanical Properties of Cast Titanium Alloys

Abstract

In order to develop a new kind of medical implant material, the microstructure and mechanical properties of cast Ti–Si alloys were investigated using small-size ingots prepared by a dental casting machine. The results show that the addition of silicon significantly changes the microstructure of titanium alloys. The Ti₅Si₃ intermetallic compound precipitation occurs in the matrix of alpha and beta phases, when the silicon content is over 1.33 mass%. The compound is observed as a netted structure around grain boundaries of the titanium matrix when the silicon content exceeds 2.35 mass%. In addition, the Ti–Si alloys show a good combination of strength and ductility in a wide range of silicon content in contrast to the pure titanium and Ti–6Al–4V alloys. The cast Ti–Si alloys are promising candidates for dental applications because of a good balance between strength and ductility.