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Freckle prediction model incorporating geometrical effects for Ni-based single-crystal superalloy components

journal contribution
posted on 2024-02-12, 16:54 authored by Yang Liu, Fu Wang, Dexin Ma, Qiang Yang, Weitai Xu, Yunxing Zhao, Hongbiao Dong, Yong Liu, Dichen Li

A freckle is a grain defect frequently found in Ni-based single-crystal (SC) superalloy castings resulting in a high scrap rate. A precise prediction of the defect before production is of great importance, especially for the complex-shaped blades and vanes. Without reckoning geometrical effects, the state-of-the-art Rayleigh number (Ra) model fails to accurately forecast the freckle formation positions. In this study, a novel Ra-based mathematical model was proposed. It not only shortened the calculation period and eliminated the physically meaningless at the singularity of the existing model, but also quantified the geometrical effects. Using the model, the Ra at every position of SC castings was calculated, which can be used to evaluate the freckling tendency of the whole casting and locate the specific positions of the freckling risk zone. A freckle-free approximate critical Rayleigh number about 1.5 was determined. A highly consistent and accurate prediction of this model was validated by comparing it with the experiments using complex-shaped SC castings, which suggests its great prospects for industrial application.

History

Author affiliation

School of Engineering, University of Leicester

Version

  • VoR (Version of Record)

Published in

Acta Materialia

Volume

266

Pagination

119702

Publisher

Elsevier BV

issn

1359-6454

Copyright date

2024

Language

en

Deposited by

Professor Hong Dong

Deposit date

2024-02-02

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