Optimization of Casting Process Parameters for Solidification Structures in Complex Superalloy Castings

Area of Science:

• Materials Science and Engineering
• Metallurgy
• Computational Materials Science

Background:

• Investment casting of nickel-based superalloys often results in inhomogeneous grain structures.
• Complex geometries and thermal gradients during solidification lead to undesirable coarse columnar grains.
• Controlling microstructure is critical for the performance of superalloy components.

Purpose of the Study:

• To optimize the grain structure of thin-walled nickel-based superalloy castings.
• To investigate the influence of casting parameters on grain morphology.
• To provide a practical approach for microstructure control in complex superalloy components.

Main Methods:

• Utilized cellular automaton-finite element (CAFE) simulations with ProCAST software.
• Modeled temperature fields and grain growth dynamics during solidification.
• Validated simulation results through experimental casting.

Main Results:

• Molten metal flow patterns significantly impact local temperature fields and grain formation.
• Simultaneous bidirectional filling minimized thermal gradients and promoted equiaxed grains.
• Lowering pouring and shell temperatures, alongside higher cooling rates, refined grain structure and improved uniformity.

Conclusions:

• Optimized casting parameters, including mold filling strategy and thermal conditions, significantly improve grain homogeneity.
• CAFE simulations coupled with experimental validation offer a powerful tool for microstructure control.
• The findings enable enhanced control over the grain structure of intricate superalloy castings.