Bioerodible Magnesium Alloy Microstructures for Endoprostheses

A method of processing a bioerodible magnesium alloy containing at least 85 weight percent magnesium for a stent comprising:

• forming an ingot or billet comprising a magnesium alloy, the magnesium alloy comprising magnesium and one or more alloying elements;
• and
• performing at least one high-strain process on the ingot or billet to form a microstructure comprising equiaxed Mg-rich solid solution-phase grains having an average grain diameter of less than or equal to 5 microns and continuous or discontinuous second-phase precipitates in grain boundaries between the equiaxed Mg-rich solid solution-phase grains, the second-phase precipitates having an average longest dimension of 0.5 micron or less.