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Title: The role of twinning deformation on the hardening response of polycrystalline magnesium from discrete dislocation dynamics simulations

Journal Article · · Acta Materialia
 [1];  [2];  [2];  [3]
  1. Sichuan Univ., Chengdu (China); Johns Hopkins Univ., Baltimore, MD (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Johns Hopkins Univ., Baltimore, MD (United States)

The mechanical response of micro-twinned polycrystalline magnesium was studied through three-dimensional discrete dislocation dynamics (DDD). A systematic interaction model between dislocations and (1012) tension twin boundaries (TBs) was proposed and introduced into the DDD framework. In addition, a nominal grain boundary (GB) model agreeing with experimental results was also introduced to mimic the GB’s barrier effect. The current simulation results show that TBs act as a strong obstacle to gliding dislocations, which contributes significantly to the hardening behavior of magnesium. On the other hand, the deformation accommodated by twinning plays a softening role. Therefore, the concave shape of the Mg stress-strain curve results from the competition between dislocation-TB induced hardening and twinning deformation induced softening. At low strain levels, twinning deformation induced softening dominates and a decreasing hardening rate is observed in Stage-I. In Stage-II, both the hardening and softening effects decline, but twinning deformation induced softening declines faster, which leads to an increasing hardening rate.

Research Organization:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
AC52-07NA27344
OSTI ID:
1257301
Alternate ID(s):
OSTI ID: 1251472; OSTI ID: 1258551
Report Number(s):
LLNL-JRNL-694178; LLNL-JRNL-694163
Journal Information:
Acta Materialia, Vol. 92; ISSN 1359-6454
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 100 works
Citation information provided by
Web of Science

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Cited By (6)

Advances in Discrete Dislocation Dynamics Modeling of Size-Affected Plasticity book January 2016
Fundamentals of Dislocation Dynamics Simulations book January 2016
The influence of lamellar twins on deformation mechanism in nanocrystalline magnesium under uniaxial compression journal July 2019
Microstructural Origin of Residual Stress Relief in Aluminum journal August 2019
Strength and ductility with {10͞11} — {10͞12} double twinning in a magnesium alloy journal April 2016
A dislocation-based model for twin growth within and across grains journal February 2018

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