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Title: Interfaces in Oxides Formed on NiAlCr Doped with Y, Hf, Ti, and B

Abstract This study applies atom probe tomography (APT) to analyze the oxide scales formed on model NiAlCr alloys doped with Hf, Y, Ti, and B. Due to its ability to measure small amounts of alloying elements in the oxide matrix and its ability to quantify segregation, t he technique offers a possibility for detailed studies of the dopant’s fate during high-temperature oxidation. Three model NiAlCr alloys with different additions of Hf, Y, Ti, and B were prepared and oxidized in O 2at 1,100°C for 100 h. All specimens showed an outer region consisting of different spinel oxides with relatively small grains and the protective Al 2O 3-oxide layer below. APT analyses focused mainly on this protective oxide layer. In all the investigated samples segregation of both Hf and Y to the oxide grain boundaries was observed and quantified. Neither B nor Ti were observed in the alumina grains or at the analyzed interfaces. The processes of formation of oxide scales and segregation of the alloying elements are discussed. The experimental challenges of the oxide analyses by APT are also addressed.
Authors:
 [1] ;  [2] ;  [2] ;  [1]
  1. Chalmers Univ. of Technology, Goteborg (Sweden)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Microscopy and Microanalysis
Additional Journal Information:
Journal Volume: 23; Journal Issue: 02; Journal ID: ISSN 1431-9276
Publisher:
Microscopy Society of America (MSA)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1394441