Modeling of the influence of oxidation on thin-walled specimens of single crystal superalloys

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Authors

  • Matthias Bensch
  • Ernst Affeldt
  • Uwe Glatzel

Colleges, School and Institutes

External organisations

  • Universität Bayreuth
  • University of Cambridge
  • MTU Aero Engines GmbH

Abstract

The microstructural evolution of uncoated single crystal superalloys is modeled taking into account the interplay between oxide growth and substrate response. Experimental investigations demonstrate that γ′ fraction of specimens with thicknesses less than 1 mm are strongly affected by oxidation. A model based on thermodynamic and kinetic data only, is presented calculating the growth kinetics of oxide scales and the resulting influence on microstructure evolution of the substrate. The model combines models for oxide growth and substrate response. Currently the main focus is on alumina (A1 2O3) scale growth as it is the most important oxide for long term behavior. A dynamic growth parameter is used to describe the growth rate of the alumina scale. The model predicts the distribution of the alloying elements as well as the evolution of the generated phases as functions of depth and oxidation time. The model has been applied to three different alloys: the strong alumina forming alloy René N5, the moderate alumina forming alloy M247LC SX and the weak alumina forming alloy SCA425+. Since the γ′ fraction is one of the most relevant factors for high temperature creep properties, the present work concentrates on the calculation of the time and space dependent γ′ precipitate profile, which is most important for thin wall specimens. The predictions have been verified with very good agreement at an oxidation temperature of 980°C with respect to alumina scale growth and γ′ fraction distribution. Predicted and measured alumina scale growth and γ′ fraction distribution for oxidation at 980°C are in very good agreement.

Details

Original languageEnglish
Title of host publicationSuperalloys 2012
Subtitle of host publicationProceedings of the 12th International Symposium on Superalloys
Publication statusPublished - 2 Oct 2012
Event12th International Symposium on Superalloys, Superalloys 2012 - Seven Springs, PA, United States
Duration: 9 Sep 201213 Sep 2012

Conference

Conference12th International Symposium on Superalloys, Superalloys 2012
CountryUnited States
CitySeven Springs, PA
Period9/09/1213/09/12

Keywords

  • Diffusion, Modeling, Nickel-base Superalloy, Oxidation, Thin-Walled