Elemental preference and atomic scale site recognition in a Co-Al-W-base superalloy

Area of Science:

• Materials Science
• Metallurgy
• Solid-State Chemistry

Background:

• Superalloys are critical for high-temperature applications.
• Understanding elemental distribution is key to optimizing alloy performance.
• The Co-Al-W-Ti-Ta system presents complex phase behavior.

Purpose of the Study:

• To determine elemental partitioning between γ' and γ phases.
• To elucidate the site preference of alloying elements within the L1₂ γ' phase.
• To provide semi-quantitative atomic column composition analysis.

Main Methods:

• Atomic scale super energy dispersive X-ray spectroscopy (EDX).
• High angle annular dark field (HAADF) imaging.
• First principles simulations (for comparison).

Main Results:

• Cobalt (Co) atoms occupy face-center positions ({1/2, 1/2, 0}).
• Aluminum (Al), Tungsten (W), Titanium (Ti), and Tantalum (Ta) atoms prefer cube-corner positions ({0, 0, 0}).
• Elemental site preference within the L1₂ γ' structure was confirmed.

Conclusions:

• The study precisely maps elemental distribution in a Co-based superalloy.
• Findings align with theoretical predictions, validating experimental methods.
• This detailed understanding aids in designing next-generation high-performance superalloys.