Powder metallurgical low-modulus Ti–Mg alloys for biomedical applications

In this work, powder metallurgical (PM) Ti–Mg alloys were prepared using combined techniques of mechanical alloying and spark plasma sintering. The alloys mainly consist of super saturations of Mg in Ti matrix, and some laminar structured Ti- and Mg-rich phases. The PM Ti–Mg alloys contain a homogeneous mixtures of nanocrystalline Mg and Ti phases. The novel microstructures result in unconventional mechanical and biological properties. It has been shown that the PM Ti–Mg alloys have a much lower compression modulus (36–50   GPa) compared to other Ti alloys, but still remain a very high compressive strength (1500–1800   MPa). In addition, the PM Ti–Mg alloys show good biocompatibility and bioactivity. Mg can dissolve in the simulated body fluids, and induce the formation of the calcium phosphate layer. The compression modulus of PM Ti–Mg alloys decreases with the amount of Mg, while the bioactivity increases. Although the corrosion resistance of Ti–Mg alloys decreases with the content of Mg, the alloys still show good stability in simulated body fluid under electrochemical conditions. The indirect and direct cytotoxicity results show that PM Ti–Mg alloys have a good biocompatibility to NIH-3T3 cells. Therefore, the PM Ti–Mg alloys are promising candidates in biomedical applications.