Influence of heat treatment on degradation behavior of bio-degradable die-cast AZ63 magnesium alloy in simulated body fluid

The effects of hybrid aging and solution treatments on the degradation of bio-degradable die-cast AZ63 magnesium alloy in 37 +/- 1 degrees C Tyrode's simulated body fluid have been investigated. The heat treatment is observed to alter the microstructure of the alloy. The amount Of beta-Mg17Al2 precipitates is larger and their distribution is more homogeneous. The homogeneous microstructure enhances the corrosion resistance of the alloy and the best corrosion rate achieved on the aged sample is approximately 1/2 of that of the untreated alloy. The corrosion mechanism of the aged alloy is dominated by filiform and pitting corrosion. Better understanding and control of surface corrosion will expedite the use of Mg alloys in biomedical implants. (C) 2006 Elsevier B.V. All rights reseved.