Thermal Characteristics, Mechanical Properties, In Vitro Degradation and Cytotoxicity of Novel Biodegradable Zn–Al–Mg and Zn–Al–Mg–xBi Alloys

Abstract

Ternary Zn–0.5Al–0.5Mg and quaternary Zn–0.5Al–0.5Mg–xBi (x = 0.1, 0.3 and 0.5) alloys were studied to evaluate the thermal and structural characteristics, mechanical properties, cytotoxicity and in vitro degradation behavior. Thermal analysis and microstructural observations showed that Zn–0.5Al–0.5Mg is composed of FCC-Al + HCP-Zn + Mg2(Zn,Al)11 while a new phase α-Mg3Bi2 appeared after the addition of Bi to the Zn–0.5Al–0.5Mg ternary alloy. The results revealed that the quaternary Zn–Al–Mg–Bi alloys have higher tensile strength, elongation and hardness but slightly lower corrosion resistance than those of the ternary Zn–Al–Mg alloy. Based on the MTT assay, the Zn–Al–Mg and Zn–Al–Mg–Bi alloys were found to be biocompatible, and thus, they can be considered for further investigation in an in vivo environment.