Presentation at Superalloy 718 & Derivatives 2023

Pritesh Parikh ^1, *, Darshan Jaware ¹, Jiangtao Zhu ¹, Karol Putyera ², Rajiv S. Soman ^2, *

¹ Eurofins Nanolab Technologies, 1708 McCarthy Blvd, Milpitas, CA 95035

² Eurofins EAG Materials Sciences LLC., 103 Commerce Boulevard, Liverpool, NY 13088, USA 

Ni-based superalloys with applications to aerospace, nuclear, electrical, and automotive industries contain various alloying elements for enhanced thermal and corrosion resistance as well as improved mechanical strength. The underlying property and long-term stability of the superalloys is directly correlated to the processing conditions, materials structure and alloying wt %. Hence, quantitative materials analysis of the alloying elements is essential for current and future superalloy development and failure investigations.

Alloying elements introduced in superalloys can segregate to grain boundaries or form nanoscale clusters either as a result of processing conditions, secondary phase formation or failure from long term use. Thus, suitable techniques at the nanoscale are necessary for a quantitative analysis and to understand the effect of clusters and segregation on material properties. APT (atom probe tomography) is the only analysis technique that can provide 3D elemental distribution with nm spatial resolution and up to 10 ppm chemical sensitivity to investigate both grain boundary segregation and clusters. Moreover, new processing techniques including additive manufacturing and nanoparticle-based alloys, further require suitable analytical techniques at the nanoscale, like APT, to identify chemical compositions.

Herein, we use APT to better understand the influence of nanoscale effects in standard samples of a widely used Ni based superalloy. Our analysis reveals differences in elemental distributions at low wt % that are responsible for material properties such as mechanical strength and oxidation resistance. We also compare bulk analysis using GDMS (glow discharge mass spectrometry), ICP-MS (inductively coupled plasma mass spectrometry) with APT to show localized fluctuations in the compositions.