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Published on: March 7, 2018
Modeling grain selection for single-crystal thin-wall inconel 718 tubes by laser powder bed fusion
Hussein Zein1, Waleed H El-Garaihy2, Abdulrahman I Alateyah3
1Department of Mechanical Engineering, College of Engineering, Qassim University, 52571, Buraydah, Saudi Arabia.
Scientific Reports
|July 13, 2026
Summary
This study introduces a geometry-assisted grain selection strategy for Laser Powder Bed Fusion (LPBF) of Inconel 718 tubes. Optimized spiral selectors promote single-grain survival by controlling thermal conditions and residual stresses.
Area of Science:
- Materials Science
- Additive Manufacturing
- Metallurgy
Background:
- Laser Powder Bed Fusion (LPBF) enables high-performance superalloy components.
- Achieving single-crystal structures in LPBF is challenging due to grain growth.
- Inconel 718 is a critical nickel-based superalloy for demanding applications.
Purpose of the Study:
- To develop a geometry-assisted grain selection strategy for single-crystal Inconel 718 tubes fabricated via LPBF.
- To identify optimal geometric parameters for spiral grain selectors.
- To establish a simulation-driven methodology for promoting single-grain survival.
Main Methods:
- Utilized a thermo-mechanical simulation framework (Simufact Additive).
- Evaluated seventy geometric configurations of spiral grain selectors.
- Analyzed macro-scale thermal indicators (G, |dT/dt|, R, G/R ratio) and residual stresses.
Main Results:
- Four-turn spiral selectors with 15°-20° take-off angles and small wire diameters yielded optimal conditions.
- Optimal geometries exhibited stable thermal gradients, favorable G/R ratios, and moderate residual stresses.
- Two-turn configurations were insufficient for thermal confinement.
Conclusions:
- A simulation-driven approach can identify geometries promoting single-grain survival in LPBF.
- Geometry-assisted grain selection is a viable strategy for fabricating single-crystal superalloy components.
- Optimized spiral selectors are crucial for controlling microstructure in thin-wall Inconel 718 parts.
