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Title: Correlative characterization of primary Al{sub 3}(Sc,Zr) phase in an Al–Zn–Mg based alloy

Three-dimensional electron backscatter diffraction, focused ion beam, transmission electron microscopy and energy filtered transmission electron microscopy were employed to investigate the structural information of primary Al{sub 3}(Sc,Zr) phase, i.e. size, shape, element distribution and orientation relationship with the α-Al matrix. It was found that (i) most primary Al{sub 3}(Sc,Zr) phases have a cubic three-dimensional morphology, with a size of about 6–10 μm, (ii) most primary Al{sub 3}(Sc,Zr) phases are located within the α-Al matrix, and exhibit a cube to cube orientation relationship with the α-Al matrix, and (iii) a layer by layer growth was observed within primary Al{sub 3}(Sc,Zr) phases. Al, Cu, Si and Fe are enriched in the α-Al matrix between the layers of cellular eutectic Al{sub 3}(Sc,Zr) phase, while Sc, Ti and Zr are enriched in small Al{sub 3}(Sc,Zr) phases. A peritectic reaction and subsequent eutectic reaction between Al{sub 3}Sc and Al was proposed to interpret the observed layer by layer growth. This paper demonstrates that the presence of impurities (Fe, Si, Cu, Ti) in the diffusion field surrounding the growing Al{sub 3}(Sc,Zr) particle enhances the heterogeneous nucleation of Al{sub 3}(Sc,Zr) phases. - Highlights: • Most fine cubic primary Al{sub 3}(Sc,Zr) phases were observed within the α-Al matrix.more » • A layer by layer growth within primary Al{sub 3}(Sc,Zr) phase was observed. • A peritectic and subsequent eutectic reaction between Al{sub 3}Sc and Al was proposed. • Impurities in diffusion fields enhance heterogeneous nucleation of Al{sub 3}(Sc,Zr)« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [3] ;  [1] ;  [5]
  1. Institute of Casting Research, Montanuniversität Leoben, A-8700 Leoben (Austria)
  2. Materials Center Leoben Forschung GmbH, A-8700 Leoben (Austria)
  3. Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Center for Electron Microscopy (Austria)
  4. Department of Materials Physics, Montanuniversität Leoben, Erich Schmid Institute of Materials Science of the Austrian Academy of Sciences, A-8700 Leoben (Austria)
  5. (Austria)
Publication Date:
OSTI Identifier:
22476070
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 102; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALLOYS; ALUMINIUM COMPOUNDS; DIFFRACTION; DIFFUSION; DISTRIBUTION; EUTECTICS; FILTERS; GRAIN REFINEMENT; IMPURITIES; ION BEAMS; LAYERS; MAGNESIUM COMPOUNDS; NUCLEATION; ORIENTATION; PRECIPITATION; SCANDIUM ADDITIONS; THREE-DIMENSIONAL CALCULATIONS; TRANSMISSION ELECTRON MICROSCOPY; ZINC COMPOUNDS; ZIRCONIUM COMPOUNDS