Microstructure and corrosion resistance of powder metallurgical Ti-Nb-Zr-Mg alloys with low modulus for biomedical application

Due to their bioinert nature, titanium alloys show poor bone-implant integration and insufficient osseointegration in vivo. In this study, a series of low elastic modulus bioactive titanium alloys with a nominal composition of Ti-13Nb-13Zr-1.25 Mg (wt%) were prepared using mechanical alloying and spark plasma sintering techniques. The microstructures, mechanical properties, degradation behaviors and in vitro bioactivities of these alloys were systematically investigated. After sintering at 700 degrees C, the alpha-Ti, 8-Ti and Nb (Zr)-rich phases were present, and the Mg was uniformly distributed. In addition to above-mentioned phases, the alpha '' phase was found after sintering at 800 degrees C or 900 degrees C. The density, elastic modulus, yield strength, ultimate compressive strength and corrosion resistance all increased with increasing sintering temperature. After sintering at 900 degrees C, the alloy exhibited high density (99.8%), good compressive strength (1417.2 MPa) and excellent corrosion resistance. In addition, it had a lower elastic modulus (-69 GPa) than that of the biomedical alloy Ti-13Nb-13Zr (-80 GPa). In vitro experiments showed that the alloys sintered at either 800 degrees C or 900 degrees C promoted cell adhesion and proliferation. However, the alloy sintered at 700 degrees C inhibited cell proliferation, which was due to the greater release of Mg2}. Thus, the optimally-processed Ti-Nb-Zr-Mg alloy sintered at 900 degrees C shows immense potential as a biomedical material.

Automated summary

In this study, low elastic modulus bioactive titanium alloys were prepared and their microstructures, mechanical properties, degradation behaviors, and in vitro bioactivities were systematically investigated. The results showed that increasing the sintering temperature improved the density, elastic modulus, yield strength, ultimate compressive strength, and corrosion resistance of the alloy. The alloy sintered at 900 degrees C exhibited excellent performance and showed immense potential as a biomedical material.