Mg-Zn-Sn alloy Mg-alloys WE43/HA composite absorbable absorbable implants absorbable metal alloy accumulation bioabsorbable metals bioactive resorbable plate bioactivity bioceramics biocompatibility biodegradable magnesium implants biodegradable material biodegradation biomaterials biomechanical loading evaluation bone surgery coating corrosion corrosion behavior corrosion rate cytotoxicity degradation degradation behavior electrochemistry fracture fixation friction stir processing hydrogen evolution in-vivo biocompatibility