A parametric study of the microstructural evolution of an advanced Ni-based superalloy powder when consolidated using Field Assisted Sintering Technology, compared to a hot isostatic pressing benchmark

Abstract

The use of Field Assisted Sintering Technology (FAST) is examined for the consolidation of an advanced Ni-based superalloy powder feedstock. FAST processed material was directly compared to a benchmark material prepared via hot isostatic pressing (HIP) where it was found that density, hardness values and microstructures were comparable. FAST enables the retainment of the prior particle grain morphology when using sintering dwell times ranging from 10 to 240 min. The application of dwell temperatures above the γ′ solvus of the alloy resulted in significant grain growth. Measured densities reveal that the applied load and dwell time used during sintering have minimal effect on the final density of the consolidated material. The crystallographic texture was also shown to be isotropic in FAST consolidated material. This study demonstrates that FAST is potentially a viable complementary and/or alternative processing route for consolidating Ni-based superalloy powders.

Keywords

• Field assisted sintering technology/spark plasma sintering (FAST/SPS)
• Ni-based superalloys
• Powder consolidation
• Prior particle boundaries
• Gamma prime γ′ precipitation
• Microstructure characterisation