Cellular Automata Simulation of Grain Growth of Powder Metallurgy Nickel-Based Superalloy

TL;DR

This study develops a 2D Cellular Automata model to simulate grain growth in nickel-based superalloys, revealing how primary {b3} ' phase size and volume fraction influence grain growth during heat treatment.

Contribution

The paper introduces a CA model that accurately predicts grain growth behavior considering primary {b3} ' phase effects, validated against experimental data with less than 10% error.

Findings

CA model fits experimental data with <10% error

Grain growth follows Zener relation in simulations

Minimum Zener coefficient n is 0.23 for 2.8 μm primary b3' particles

Abstract

Primary {\gamma}' phase instead of carbides and borides plays an important role in suppressing grain growth during solution at 1433K of FGH98 nickel-based polycrystalline alloys. Results illustrate that as-fabricated FGH98 has equiaxed grain structure and after heat treatment, grains remain equiaxed but grow larger. In order to clarify the effects of the size and volume fraction of the primary {\gamma}' phase on the grain growth during heat treatment, this paper establish a 2D Cellular Automata (CA) model based on the thermal activation and the lowest energy principle. The CA results are compared with the experimental results and show a good fit with an error less than 10%. Grain growth kinetics are depicted and simulations in real time for various sizes and volume fractions of primary {\gamma}' particles work out well with the Zener relation. The coefficient n value in Zener relation is theoretically calculated and its minimum value is 0.23 when the radius of primary {\gamma}' is 2.8{\mu}m.