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-6A1-4V alloys. The cast Ti-Si alloys are promising candidates for dental applications because of a good balance between strength and ductility.