Ductile biodegradable Mg-based metallic glasses with excellent biocompatibility

Magnesium-based metallic glasses (MMGs) show intriguing potentials for application as implantable biomaterials owing to their disordered atomic structure, good biodegradability, low elastic modulus, high strength, and large elasticity. However, despite of all these advantages, their brittleness is their Achilles' heel, which severely limits their application as biomedical materials. In the current study, a significantly improved ductility of MMGs under bending and tensile loading through minor alloying with rare-earth element ytterbium (Yb) at an atomic concentration of 2 and 4% is reported. The enhanced ductility is attributed to the increased density of shear bands close to fracture end and larger plastic zones on the fracture surface. In comparison with that of Yb-free control, in vitro cell culture study confirms an improved biocompatibility of MMGs alloyed with Yb as determined by MTT, live-dead, and cytoskeleton staining assays, respectively. Mg-based metallic glasses have good ductility and excellent cell compatibility when properly alloyed by Yb. The good bending and tensile ductility is likely due to the formation of dense shear bands and large plastic zones. The improved cell compatibility can be attributed to the good corrosion resistance and the reduced release of cations and hydrogen.