A new perspective about the surface structure of FGH96 superalloys powders.

Understanding of the surface structure of FGH96 alloy powders has implications for the subsequent evolution in sintering. The results from this work indicate that the oxide film of powder surface was composed of TiO 2 particles and homogeneous oxide layer. Two types of carbides with size of about 30–50 nm and 250 nm are founded, which can further lead to the differences in low-temperature oxidation during the atomization process, resulting in the presence of amorphous TiO 2 particles of similar size to the precipitates above them. The oxidation of the γ leads to a uniform amorphous oxide layer with a thickness of approximately 14 nm above the powder matrix. [Display omitted] • The correspondence between surface morphology and structure was established. • The M(Ti, Nb)C is precipitated on the powder surface during atomization. • Different oxidation products of powders due to the existence of precipitated phase. • Oxide film of powder surface consists of amorphous oxide layer and TiO 2 particles. [ABSTRACT FROM AUTHOR]