Fabrication and characterization of the Ti-۶Al-۴V/Mg scaffold

Ti–۶Al–۴V scaffolds were fabricated by powder metallurgical space holder technique in this research. The most added magnesium (Mg) powder was evaporated and a skeleton of Ti-۶Al-۴V alloy was produced. For this purpose Ti-۶Al-۴V and Mg powders mixture compacted in a steel die by applying uniaxial pressure of ۵۰۰ MPa before sintering the green product in a sealed quartz tubes at ۹۰۰ °C for ۲ hours. Employing Archimedes’ principle and an Image Tool software, the total and open volume percent of porosities within the scaffolds were found to be in the range of ۴۶-۶۴% and ۴۱-۴۷%, respectively. Bioactivity properties of the scaffolds were investigated in a simulated body fluid (SBF). Scanning electron microscopy (SEM) and Energy dispersive spectroscopy (EDS) were used for studying the specimens’ surfaces after immersing them for ۲۸ days. The results showed that the amounts of calcium (Ca) and phosphor (P) deposited into the porous areas were more than that of smooth surfaces due to the presence of Mg particles within the pores which provoked formation of apatite layers. Changing in the pH values of the SBF during ۱۸ days of immersion revealed that gradual improvement in pH level due to releasing OHˉ .Using atomic absorption spectroscopy (AAS) indicated that by increasing Mg content of scaffolds, Ca concentration of SBF decreased which is an indication of apatite formation on the scaffold. Results of SBF bioactivity assays exhibited that the scaffold with ۶۰ vol.% Mg has the best ability to induce apatite nucleation.

Keywords:

Ti-۶Al-۴V , Scaffold , Mg , Powder Metallurgy , SBF