Characterization of an Mg-2Zn-1Ca 1β-TCP Composite Fabricated by High Shear Solidification and ECAE

Abstract

A biodegradable Mg matrix and nano β-tricalcium phosphate (β-TCP) particles reinforced composite Mg-2Zn-1Ca-1β-TCP was fabricated for biomedical applications by high shear solidification combined with equal channel angular extrusion (ECAE). Optical and electron microscopy, EBSD analysis and mechanical and electrochemical testing were carried out to characterize the microstructure, texture and mechanical and corrosion resistance of the material. The high shear solidification resulted in a fine and uniform grain structure with β-TCP particles evenly distributed in the matrix in clusters of 5-20 μm in size. The as-cast microstructure was replaced by a refined deformation microstructure after ECAE processing at 300 °C, during which the β-TCP particle clusters were largely dispersed, giving rise to the formation of a uniform dispersion of individual β-TCP particles in the matrix. The deformation processing by ECAE increased both the hardness and the corrosion resistance of the material. The dispersed individual nano β-TCP particles were considered to be an important factor responsible for the improved corrosion resistance after ECAE. Texture development during ECAE and its effect on the corrosion resistance was examined.