EFFECTS OF HYDROGEN ANNEALING, SULFUR SEGREGATION AND DIFFUSION ON THE CYCLIC OXIDATION RESISTANCE OF SUPERALLOYS - A REVIEW

[摘要] This review is based on the phenomenon of improved oxide scale adhesion for desulfurized superalloys. The proposed adhesion mechanism involves sulfur interfacial segregation and scale-metal bond weakening. Sulfur surface segregation on superalloys is examined as a function of temperature and sulfur content, and is related to the classical behaviour predicted by the McLean isotherm. Effective desulfurization to less than 1 ppmw can be accomplished by hydrogen annealing and is described by sulfur diffusion kinetics in nickel. Hydrogen annealing results in excellent cyclic oxidation resistance for a number of advanced superalloys. The concept of a critical sulfur content is discussed in terms of practical annealing conditions and section thicknesses.

[发布日期] 1994-12-15

[关键词] ADHESION;OXIDATION;SULFUR;SURFACE SEGREGATION