Low-temperature phase transitions in the EZ33A Mg-cast alloy have been investigated. Based on the structure assessment of the alloy after annealing at 150 °C (1826 h) and at 200 °C (2371 h) a grain boundary wetting transition by a second solid phase was documented. Within a 50 °C temperature range, substantial differences in the α(Mg) grain boundary fraction wetted by the (Mg,Zn)₁₂RE intermetallic were observed. In contrast to what was reported in the literature, two different types of precipitates were found within α(Mg) grains. With increasing annealing temperatures, both types of precipitates dissolved.

Ultra-fine grained and even nanostructured magnesium alloys obtained by processing with methods of severe plastic deformation (SPD) are promising biomaterials for absorbable orthopaedic implants due to their enhanced mechanical properties, adequate corrosion resistance and biocompatibility. This paper presents an overview of the impact of the most important SPD methods – equal-channel angular pressing (ECAP) and high-pressure torsion (HPT) – on microstructure refinement and improvement of the mechanical properties of magnesium alloys intended for medical implants. Several selected groups of magnesium alloys which have the potential for use as bioabsorbable implants are discussed. The presented results of many years of research indicate the beneficial effect of SPD methods on obtaining ultra-fine and even nanostructures of magnesium alloys with improved mechanical and better functional properties, which are necessary for bioabsorbable implants.