Introducing an ultralight, high-strength, biodegradable Mg-4Li-1Ca alloy

Mg-4Li-1Ca ternary alloy produced by melting from two binary master alloys was subjected to two-step rolling undergoing 60% thickness reduction in each. The density of the wrought alloy was found to be 1.56  0.3 gm/cm3—lower than the density of any commercial Mg alloys. Rolling resulted in a remarkable improvement in tensile strength (250 MPa) owing to substantial microstructure refinement and a rather uniform dispersion of second phase particles. Biodegradation behaviour in simulated physiological environments confirmed the formation of a hydroxyapatite layer ensuring good biocompatibility of the alloy. The live/dead staining results with osteoblast cells showed a substantial fraction of live cells upon seven days of culture, which indicates excellent cytocompatibility of the alloy. This was further supported by the scanning electron microscopy evidence. We conclude that the new Mg-4Li-1Ca alloy is a promising material for medical implants possessing a favourable combination of properties, including low density, high strength, and promising cell response.