Design and development of large-diameter Mg-Zn-Ca bulk metallic glass for biomedical applications: A mechanical and corrosion perspective
Rajesh Kumari Rajendran, Divyanshu Aggarwal, Manon Bonvalet Rolland, Cosmin Gruescu, Rajashekhara Shabadi
Abstract
Being amorphous, bulk metallic glasses (BMGs) exhibit superior properties compared to their crystalline alloy counterparts. Amorphous materials are preferred for their excellent mechanical and degradation behavior. Among the various elemental combinations, MgZnCa has shown the most promising results, as evidenced by the literature. However, the maximum achievable size of the metallic glasses remains a bottleneck. The current work aims to address this challenge and achieve it splendidly with a systematic methodology by developing larger diameter MgZnCa BMGs through vacuum induction casting using a specially designed copper mold. The optimal composition was formalized for glass formation of the Mg 65 Zn 31 Ca 4 system using the CALPHAD technique. As a result, a 6.5 mm diameter glassy alloy was successfully obtained. The XRD and TEM analysis experiments demonstrated a perfect amorphous structure of the developed sample. The anti-corrosion properties of the as-cast glass increased, followed by enhancement in the yield strength and hardness in contrast to the properties of the human bone. Furthermore, the surface wettability analysis showed an adequate surface obtained to promote fibroblast adhesion. In conclusion, the current work represents a notable progress in the fabrication of larger-diameter MgZnCa BMG for biomedical applications, considering that the biggest diameter ever reported in the MgZnCa system was more than a decade ago. • A novel composition of Mg-Zn-Ca was deduced (Mg 65 Zn 31 Ca 4 ) from the CALPHAD calculations. • Experimentally proved the formation of the glass at this new composition. • The diameter of the bulk metallic glass is 30 % higher than what's reported in the literature for Mg-Zn-Ca bulk metallic glasses. • Excellent corrosion resistance of the Mg 65 Zn 31 Ca 4 glass in both 1 wt% NaCl and simulated body fluid (SBF) solutions.