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Title: Three-dimensional local residual stress and orientation gradients near graphite nodules in ductile cast iron [3D local residual stress and orientation gradients near graphite nodules in ductile cast iron]

A synchrotron technique, differential aperture X-ray microscopy (DAXM), has been applied to characterize the microstructure and analyze the local mesoscale residual elastic strain fields around graphite nodules embedded in ferrite matrix grains in ductile cast iron. Compressive residual elastic strains are measured with a maximum strain of ~6.5–8 × 10 –4 near the graphite nodules extending into the matrix about 20 μm, where the elastic strain is near zero. The experimental data are compared with a strain gradient calculated by a finite element model, and good accord has been found but with a significant overprediction of the maximum strain. This is discussed in terms of stress relaxation during cooling or during storage by plastic deformation of the nodule, the matrix or both. Furthermore, relaxation by plastic deformation of the ferrite is demonstrated by the formation of low energy dislocation cell structure also quantified by the DAXM technique.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [1] ;  [3] ;  [2] ;  [4]
  1. Technical Univ. of Denmark, Roskilde (Denmark)
  2. Technical Univ. of Denmark, Lyngby (Denmark)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 121; Journal Issue: C; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Cast iron; Differential aperture X-ray microscopy (DAXM); Finite element modeling; Plastic deformation; Residual strain/stress
OSTI Identifier:
1411946
Alternate Identifier(s):
OSTI ID: 1397743