"Effect of Spacer on the Fabrication and Properties of TiZr-Based BMG Foams for Bio-Implant Applications"

Abstract

Biocompatible TiZr-based BMG foams (with the composition of Ti 42 Zr 35 Si 5 Ta 3 Co 12.5 Sn 2.5 in at. %) were successfully fabricated by using Cu spacer particles. The TiZrbased MG powder mixed with Cu spacer particles in the various ratio of volume fractions based on the desired porosity. The mixed powder was then processed by a hot pressing machine in 300 MPa of pressure, 520°C temperature, and 5 minutes of holding time. The porous sample was obtained after removing Cu spacer particles with a 50:50 concentrated HNO 3 :H 2 O mixed solution at room temperature. By SEM examination, the porosity parameters of fabricated porous samples were confirmed similar to the human bones (100-325 μm) which resulting in pore sizes of 120 µm. The XRD and TEM analysis exhibit that the porous samples retain their amorphous state after the hot pressing process. Similar mechanical properties to the human bones can be obtained by controlling the porosity of the samples based on the Gibson and Ashby model. Increasing porosity of the samples from 2% to 67.9% confirmed a decrease in the compressive strength (from 1261 to 76 MPa) and Young's modulus (from 79.7 to 4.6 GPa). In the biocompatibility test, the fabricated porous sample by using Cu spacer particles shows that cell viability increased with increasing incubation time which means that the cell was growing continuously. After 8 h incubation, the cell migration was observed and showing a distance reduction of approximately 600 µm. The results of calcium deposition rate are always higher than 100% show that the sample positively biocompatible in the human body.Recent studies have found that lower Young's modulus can be obtained by the development of titanium-based BMG since