Patent ID: 8460485

Claim:
A method of forming fine grains of a Co—Cr—Mo alloy with nitrogen addition, comprising: subjecting a Co—Cr—Mo alloy with nitrogen addition composed of 26 to 35% by weight of Cr, 2 to 8% by weight of Mo, 0.1 to 0.3% by weight of N, and balance of Co to a solution treatment; subjecting the alloy to an isothermal aging treatment by holding the alloy at 670 to 830° C. for a predetermined period of time to form a multi-phase structure composed of an s-phase and a Cr nitride by means of the isothermal aging treatment; cooling the alloy; and subjecting the alloy to a reverse transformation treatment in which the alloy is heated at a temperature range of 870 to 1100° C. for reverse transformation to a single γ-phase from the multi-phase structure composed of an s-phase and a Cr nitride.