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Title: Shear-Coupled Grain Growth and Texture Development in a Nanocrystalline Ni-Fe Alloy during Cold Rolling

Abstract

The evolution of texture, grain size, grain shape, dislocation and twin density has been determined by synchrotron X-ray diffraction and line profile analysis in a nanocrystalline Ni- Fe alloy after cold rolling along different directions related to the initial fiber and the long axis of grains. The texture evolution has been simulated by the Taylor-type relaxed constraints viscoplastic polycrystal model. The simulations were based on the activity of partial dislocations in correlation with the experimental results of dislocation density determination. The concept of stress-induced shear-coupling is supported and strengthened by both the texture simulations and the experimentally determined evolution of the microstructure parameters. Grain-growth and texture evolution are shown to proceed by the shear-coupling mechanism supported by dislocation activity as long as the grain size is not smaller than about 20 nm.

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Basic Energy Sciences - Scientific User Facilities Division
OSTI Identifier:
1392332
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science; Journal Volume: 47; Journal Issue: 12
Country of Publication:
United States
Language:
English
Subject:
Dislocation mechanism of grain growth; Texture simulation; X-ray line profile analysis; grain growth; nanocrystalline Ni-Fe alloy; strain-induced shear-coupling

Citation Formats

Li, Li, Ungár, Tamás, Toth, Laszlo S., Skrotzki, Werner, Wang, Yan Dong, Ren, Yang, Choo, Hahn, Fogarassy, Zsolt, Zhou, X. T., and Liaw, Peter K. Shear-Coupled Grain Growth and Texture Development in a Nanocrystalline Ni-Fe Alloy during Cold Rolling. United States: N. p., 2016. Web. doi:10.1007/s11661-016-3753-7.
Li, Li, Ungár, Tamás, Toth, Laszlo S., Skrotzki, Werner, Wang, Yan Dong, Ren, Yang, Choo, Hahn, Fogarassy, Zsolt, Zhou, X. T., & Liaw, Peter K. Shear-Coupled Grain Growth and Texture Development in a Nanocrystalline Ni-Fe Alloy during Cold Rolling. United States. doi:10.1007/s11661-016-3753-7.
Li, Li, Ungár, Tamás, Toth, Laszlo S., Skrotzki, Werner, Wang, Yan Dong, Ren, Yang, Choo, Hahn, Fogarassy, Zsolt, Zhou, X. T., and Liaw, Peter K. Mon . "Shear-Coupled Grain Growth and Texture Development in a Nanocrystalline Ni-Fe Alloy during Cold Rolling". United States. doi:10.1007/s11661-016-3753-7.
@article{osti_1392332,
title = {Shear-Coupled Grain Growth and Texture Development in a Nanocrystalline Ni-Fe Alloy during Cold Rolling},
author = {Li, Li and Ungár, Tamás and Toth, Laszlo S. and Skrotzki, Werner and Wang, Yan Dong and Ren, Yang and Choo, Hahn and Fogarassy, Zsolt and Zhou, X. T. and Liaw, Peter K.},
abstractNote = {The evolution of texture, grain size, grain shape, dislocation and twin density has been determined by synchrotron X-ray diffraction and line profile analysis in a nanocrystalline Ni- Fe alloy after cold rolling along different directions related to the initial fiber and the long axis of grains. The texture evolution has been simulated by the Taylor-type relaxed constraints viscoplastic polycrystal model. The simulations were based on the activity of partial dislocations in correlation with the experimental results of dislocation density determination. The concept of stress-induced shear-coupling is supported and strengthened by both the texture simulations and the experimentally determined evolution of the microstructure parameters. Grain-growth and texture evolution are shown to proceed by the shear-coupling mechanism supported by dislocation activity as long as the grain size is not smaller than about 20 nm.},
doi = {10.1007/s11661-016-3753-7},
journal = {Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science},
number = 12,
volume = 47,
place = {United States},
year = {Mon Sep 19 00:00:00 EDT 2016},
month = {Mon Sep 19 00:00:00 EDT 2016}
}
  • Microstructures in nanocrystalline Ni-Fe alloys during cold rolling are quantitatively investigated by synchrotron high-energy X-ray diffraction. It is found that rolling leads to an obvious reduction in the densities of both dislocations and twins and an increase in crystallite size. A huge dislocation flux flows through the grains during rolling, even though only a small fraction remains in the specimen after rolling. A mechanically induced relaxation of the initial high-excited state of materials is revealed.
  • Stress softening after cold rolling is observed in an electrodeposited nanocrystalline Ni-Fe alloy. The grain-size distribution becomes much broader after the cold rolling. Microstructure changes, though moderate, such as simultaneously decreased dislocation and twin densities with grain growth during cold rolling, are systematically proved by synchrotron high-energy X-ray diffraction, and transmission-electron microscopy and differential-scanning calorimetry (DSC). The amorphous fractions in the form of grain boundaries are evidenced by the diffuse-background scatterings and large DSC values. Partial dislocation separation calculation, a dislocation mean free path and annihilation model, and texture development together reveal that the current nanocrystalline Ni-Fe alloy exhibits themore » combined behavior of perfect dislocation slip and grain-boundary mediated deformation.« less
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