Paper Title:
Diffusion Enhanced Rumpling Associated with Martensitic Transformation upon Cycling of Aluminide Bond-Coats
  Abstract

In this work, β-NiAl aluminide coatings (cubic B2 structure) deposited on a DS substrate have been isothermally as well as cyclically oxidised at 1100°C for up to 240 h to study the diffusion mechanisms associated with the growth of the oxide scales. A 24 h cycle has been shown to promote enhanced Al depletion, thus requiring a sufficient Al flux to maintain a protective oxide scale. Glancing incidence X-ray diffraction (GI-XRD) combined to electron microscopy (FEG-ESEM / EDS) has been carried out to characterize the evolution of the phases induced by the progressive Al depletion into the coating. The results show that upon cycling, specimens undergo significant oxide scale spallation and increased roughness that can be ascribed to both the growth stresses and the phase transformation contribution whereas the coating has barely evolved after 240 h of isothermal exposure. In particular, the martensitic transformation (tetragonal L10 structure) that accompanies thermal cycling was found to be much more significant than the evolution of the γ’-Ni3Al (cubic L12 structure) phase over the same thermal cycle and therefore the B2 to martensite transformation could originate the progressive roughening of the surface. Conversely, upon isothermal exposure, the coating exhibited a typical alumina scale with almost no spallation and the appearance of rumples.

  Info
Periodical
Defect and Diffusion Forum (Volumes 289-292)
Edited by
A. Agüero, J.M. Albella, M.P. Hierro, J. Phillibert and F.J. Pérez Trujillo
Pages
227-233
DOI
10.4028/www.scientific.net/DDF.289-292.227
Citation
B. Bouchaud, J. Balmain, F. Pedraza, "Diffusion Enhanced Rumpling Associated with Martensitic Transformation upon Cycling of Aluminide Bond-Coats", Defect and Diffusion Forum, Vols. 289-292, pp. 227-233, 2009
Online since
April 2009
Export
Price
$32.00
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: M. Reid, Michael J. Pomeroy, Jeremy S. Robinson
343
Authors: Yuki Matsuoka, Kazuyoshi Chikugo, Takakazu Suzuki, Yasuo Matsunaga, Shigeji Taniguchi
Abstract:Ru coating prior to aluminizing is one of the effective methods to reduce the harmful intermediate layer that forms under the coating (SRZ)...
111
Authors: Rabi Sankar Dutta, Chelakkattu Yusufali, Sanjib Majumdar, Raman Kumar Mishra, Chetan Parkash Kaushik, Rohidas Jagannath Kshirsagar, Ulhas Digambar Kulkarni, Gautam Kumar Dey
Chapter 10: Functional and Nano Materials
Abstract:Aluminides were formed on Ni-Cr-Fe based superalloy 690 substrates using pack aluminization process at 1273 K in controlled atmosphere....
733
Authors: M.A. González, D.I. Martínez, C.T. Saucedo, I. Guzmán, J.C. Díaz
Abstract:This work presents the degradation mechanism of the platinum modified aluminide diffusion coating of the GTD 111 SC Ni-base superalloy...
29