Microstructure and performance of a biodegradable Mg–1Ca–2Zn–1TCP composite fabricated by combined solidification and deformation processing

A biodegradable magnesium matrix and nano β-tricalcium phosphate (β-TCP) particles reinforced composite Mg–2Zn–0.5Ca–1β-TCP was fabricated for biomedical applications by high shear solidification and equal channel angular extrusion (ECAE). The high shear solidification resulted in a fine and uniform grain structure with β-TCP particle clusters of 5–25 μm in size evenly distributed in the magnesium alloy matrix while the ECAE processing led to further microstructural refinement and a uniform dispersoid of β-TCP particles in the matrix, giving rise to an increase in both the hardness and the corrosion resistance for the material. The formation of a passive surface film consisting of β-TCP nano particles was considered to be an important reason for the increased corrosion performance.