In recent years, biodegradable Mg-based materials have been increasingly studied to be used in the medical industry and beyond. A way to improve biodegradability rate in sync with the healing process of the natural human bone is to alloy Mg with other biocompatible elements. The aim of this research was to improve biodegradability rate and biocompatibility of Mg-0.5Ca alloy through addition of Y in 0.5/1.0/1.5/2.0/3.0wt.%. To characterize the chemical composition and microstructure of experimental Mg alloys, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), light microscopy (LM), and X-ray diffraction (XRD) were used. The linear polarization resistance (LPR) method was used to calculate corrosion rate as a measure of biodegradability rate. The cytocompatibility was evaluated by MTT assay (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide) and fluorescence microscopy. Depending on chemical composition, the dendritic α-Mg solid solution, as well as lamellar Mg2Ca and Mg24Y5 intermetallic compounds were found. The lower biodegradability rates were found for Mg-0.5Ca-2.0Y and Mg-0.5Ca-3.0Y which have correlated with values of cell viability. The addition of 2–3 wt.%Y in the Mg-0.5Ca alloy improved both the biodegradability rate and cytocompatibility behavior.

No abstract

Ultralight magnesium alloys are wide used in the medical field, especially for biodegradable implants. Although they are wide used, magnesium has low corrosion resistance. To improve this resistance, different types of alloys based on magnesium and Ca, Mn, Zr and Y can be developed. The main goal of the present paper is to investigate the properties of some master alloy based on Mg-X system (Ca ,Mn, Zr, Y) used in the development of biodegradable based alloys of Mg. The surface morphology was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and optical microscopy. After the XRD analysis, there was observed that some specific compounds were formed of Mg2Ca, Mg0.97Mn0.025, MgZr, Mg2Y, Mg24Y5 having the main Mg phase formed in the hexagonal structure. There were also evaluated the master alloys micro-hardness values in the range of 58.41 HV (Pure Mg), 67.97 HV (Mg-3Mn), 85.12 HV (Mg-25Zr), 131.8 HV (Mg-15Ca) and 291.45 HV (Mg-30Y). The corrosion resistance was developed using electrochemical testing in specific medium and there is shown that the corrosion rate increased significantly for the master alloys investigated, rather than pure magnesium. As a final conclusion structural properties of these alloys recommend them for usage as medical implants.

In recent years, researchers have been able to identify new materials with special properties that can be used in major medical fields. Magnesium-based materials used in orthopedics are an important alternative, being the third generation of biocompatible materials. A biodegradable magnesium-based material has the ability to degrade at a certain rate, is biocompatible, and together with other alloying elements ensures osteointegration. Mg-0.5Ca-xY biodegradable alloys will be developed in an induction melting furnace using ceramic crucibles, melting at 710-720 °C in the controlled atmosphere of 5.0 Ar. SEM analyses and X-ray diffraction reveals the size distribution of Mg-sized grains, with a hexagonal lattice and formation of compounds with the two alloying elements: Mg2Ca, Mg2Y, Mg24Y5uniformly arranged in the α-Mg matrix. The alloying elements influence the microstructure, the size of the α-Mg grains decreasing considerably.

No abstract