Cobalt-Free Nickel-Base Wrought Superalloys

A study has been made of the infLuenee of C, Cr, Co, MO, W, Ta, AZ, Mn, Si and Y on the high temperature oxidation resistance of a group of experimental nickel-base superaZloys. Oxidatiori. was performed in fZowing air at 1095 C (2000 F) with intermittent cycling to room temperature. Ai: additions increased resistance to oxide spaZling, and Y additions Limited both tota: mass gain and oxide spai!Ling. MO and W additions improved resistance to both mass gain and oxide spalling. Synergism between Si and each of the elements Ta, Y and AL promoted oxide spaZZing. Co was not essential for adequate oxidation resistance. Stress rupture properties similar to those of cobalt-base Haynes Alloy 188 and of Ineonel! 617 (12.5% Ccl) at 870 C (1600 F) and 1095 C (2000 F) were achieved with a cobalt-free alloy.