Characteristics of FGH4108 superalloy powder prepared by Argon atomization

Abstract

High-performance powder metallurgy (PM) superalloy turbine disk is crucial to the development of the new generation of aero-engines with a high thrust-to-weight ratio. In this study, the particle size distribution, sphericity, microstructure, defects and dendritic segregation of a newly designed FGH4108 superalloy powder were characterized, and the solidification thermodynamic parameters were calculated. The results indicate that the particle size distribution of powder is uniform and normal distribution, and the sphericity is high. As the particle size decreases, the SDAS decreases due to the increase in cooling rate. The powder microstructure transforms from dendrite to cellular structure, leading to refined microstructure. The cooling rate plays a dominant role among the influencing factors of powder structure. The powder with a particle size below 38 μm has a dense structure and essentially no defects. The powder with a particle size exceeding 38 μm contains satellite powder and hollow powder, which increase with the growth of particle size. Nano-scale dendritic segregation is present in FGH4108 powder. Elements such as W, Cr, Co, Ni, and Al are enriched in the dendrite axis, while elements like Hf, Ta, Nb, Ti, and Mo are enriched in the interdendritic region. As the particle size decreases, the degree of dendritic segregation decreases. In summary, it is recommended to select powders with a particle size range of 38–63 μm in the subsequent production process.