Download file (6.34 MB)
Download as zip (5 MB)

Collection

Citation

Description:

This manuscript investigated the possibility for CALPHAD (calculation of phase diagram) approach to predict the local phase transformation accompanied by compositional transition on the superlattice stacking fault in the γ′ precipitates in multi-component superalloys. The method is basically parallel tangent construction using the concept of the defect phases in the system of γ and γ′ phases to approximate the stacking fault. Because the important issue for the strengthening by the local phase transformation is whether the local transformed phase is ordered or disordered, the ordering was judged by the size of the stacking fault energy to form the defect phase from γ′ precipitates. In addition, since the solute partitioning ratio between defect phase and γ′ precipitates is also significant to consider the local phase transformation, predicted ratio is verified using the experimental results in the previous reports. In the case of SISF (superlattice intrinsic stacking fault), Co-base superalloys tend to form ordered defect phase, but Co-Ni-base superalloys tend to form disordered defect phase. Formability of ordered and disordered defect phase in Ni-base superalloys is calculated to be competitive each other. Predicted solute partitioning rate almost agrees with experimental one expect for W and Nb in multi-component superalloys. This discrepancy could originate from the accuracy of the physical properties of Ti and Nb in the calculation. In the case of SESF (superlattice extrinsic stacking fault), all considered alloys of Ni-base superalloys is predicted to have ordered defect phase, judged by stacking fault energy, however, predicted solute partitioning ratio is totally different from the experimental ones. This issue could originate form inaccurate physical properties of Ti and Ta in the multi-component system.

Rights:

• Creative Commons BY Attribution 4.0 International
  

  You are free to:
  Share — copy and redistribute the material in any medium or format for any purpose, even commercially.
  Adapt — remix, transform, and build upon the material for any purpose, even commercially.
  The licensor cannot revoke these freedoms as long as you follow the license terms.

Keyword: Superalloys, Stacking fault, Solute partition, Local phase transformation, Suzuki effect

Date published: 2024-09-06

Publisher: Elsevier BV

Journal:

• Next Materials (ISSN: 29498228) vol. 7 100363

Funding:

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1016/j.nxmate.2024.100363

Related item:

Other identifier(s):

Contact agent:

Updated at: 2024-09-09 16:30:26 +0900

Published on MDR: 2024-09-09 16:30:26 +0900