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This content will become publicly available on July 1, 2019

Title: Enhancing workability in sheet production of high silicon content electrical steel through large shear deformation

Enhanced workability, as characterized by the magnitude and heterogeneity of accommodated plastic strains during sheet processing, is demonstrated in high Si content Fe-Si alloys containing 4 and 6.5 wt% Si using two single-step, simple-shear deformation techniques – peeling and large strain extrusion machining (LSEM). The model Fe-Si material system was selected for its intrinsically poor material workability, and well-known applications potential in next-generation electric machines. In a comparative study of the deformation characteristics of the shear processes with conventional rolling, two distinct manifestations of workability are observed. For rolling, the relatively diffuse and unconfined deformation zone geometry leads to cracking at low strains, with sheet structures characterized by extensive deformation twinning and banding. Workpiece pre-heating is required to improve the workability in rolling. In contrast, peeling and LSEM produce continuous sheet at large plastic strains without cracking, the result of more confined deformation geometries that enhances the workability. Peeling, however, results in heterogeneous, shear-banded microstructures, pointing to a second type of workability issue – flow localization – that limits sheet processing. This shear banding is to a large extent facilitated by unrestricted flow at the sheet surface, unavoidable in peeling. With additional confinement of this free surface deformation and appropriatelymore » designed deformation zone geometry, LSEM is shown to suppress shear banding, resulting in continuous sheet with homogeneous microstructure. Thus LSEM is shown to produce the greatest enhancement in process workability for producing sheet. In conclusion, these workability findings are explained and discussed based on differences in process mechanics and deformation zone geometry.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Material, Physical, and Chemical Sciences Center
  2. Purdue Univ., West Lafayette, IN (United States). School of Materials Engineering
  3. Purdue Univ., West Lafayette, IN (United States). School of Materials Engineering, and Center for Materials Processing and Tribology
  4. Purdue Univ., West Lafayette, IN (United States). School of Industrial Engineering, and Center for Materials Processing and Tribology
Publication Date:
Report Number(s):
SAND-2018-2502J
Journal ID: ISSN 0924-0136; 661266
Grant/Contract Number:
AC04-94AL85000; EE0007868; CMMI 1562470; DMR 1610094; NA0003525
Type:
Accepted Manuscript
Journal Name:
Journal of Materials Processing Technology
Additional Journal Information:
Journal Volume: 257; Journal Issue: C; Journal ID: ISSN 0924-0136
Publisher:
Elsevier
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE); USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; workability; simple-shear deformation; machining; flow heterogeneity; sheet processing
OSTI Identifier:
1429499