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/lp/springer_journal/effect-of-squareness-of-initial-precipitates-on-creep-rupture-life-of-VTdYktldM0
- Publisher
- Springer Journals
- Copyright
- Copyright © 2018 by The Minerals, Metals & Materials Society and ASM International
- Subject
- Materials Science; Metallic Materials; Characterization and Evaluation of Materials; Structural Materials; Surfaces and Interfaces, Thin Films; Nanotechnology
- ISSN
- 1073-5623
- eISSN
- 1543-1940
- DOI
- 10.1007/s11661-018-4635-y
- Publisher site
- See Article on Publisher Site
Abstract
An approach to determination of squareness of initial γ′ precipitates (S 2D) is proposed to evaluate its effect on creep-rupture life (t r) of nickel-base single crystal (SC) superalloys. It is found that the 760/982 °C rupture life varied with the change in regional S 2D caused by redistribution of W when 1st-step aging temperature changed in full heat treatment on superalloy DD83 investigated. The longest creep-rupture life occurred at the highest value/the lowest difference in S 2D in the interdendritic regions/between the typical dendritic regions in DD83. It is also found that S 2D is a weighted function of the area fraction (F 2D), spacing (h), and size (d) of γ′ precipitates and is closely related to t r in a series of SC superalloys. In addition, the variation of S 2D with F 2D (here, thermodynamic mole fraction is approximately expressed by F 2D) through lattice misfit (δ) in the SC superalloys with F 2D ranging from ~ 60 to 75 pct is well correlated. Therefore, to reveal and to better understand these relationships and correlations may help to optimize the phase variables in order to achieve a long rupture life of SC superalloys. In addition, functions to reveal the interrelationships of F 2D, volume fraction (F 3D), S 2D, and cuboidness (S 3D) of initial γ′ precipitates are derived considering their shape changes. All of these are hoped to be helpful in practical applications and in understanding the true meaning of the related variables.
Journal
Metallurgical and Materials Transactions A – Springer Journals
Published: May 11, 2018