Embodiments of the present invention provide methods of processing cobalt alloys including, in weight percent, from 26 to 30 chromium, from 5 to 7 molybdenum, and greater than 50 cobalt, the methods comprises cold working and aging the alloys such that after aging the cobalt alloys have a hardness of at least Rockwell C 50. Other embodiments provide methods of selectively cold working at least one portion of a cobalt alloy, and subsequently aging the alloy, such after aging, the selectively cold worked portions of the alloy have a higher hardness value then portions of the alloy that were not selectively cold worked. The present invention also discloses cobalt alloys, implants, and articles of manufacture made from cobalt alloys within the present invention.