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Title: Stress and strain relaxation in magnesium AZ31 rolled plate: In-situ neutron measurement and elastic viscoplastic polycrystal modeling

Journal Article · · International Journal of Plasticity
 [1];  [1];  [2];  [1];  [1];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Georgia Inst. of Technology, Atlanta, GA (United States); Georgia Tech-CNRS, Metz (France)

Continuous mechanical tests with strain holds (stress relaxation) and with stress holds (strain relaxation) are performed simultaneously with in-situ neutron measurements to analyze the mechanisms of stress and strain relaxation in Mg AZ31 rolled plate. A dislocation activity based constitutive model, accounting for internal stress statistical distributions, is proposed and implemented into an elastic viscoplastic self-consistent (EVPSC) framework to simultaneously describe both stress and strain relaxation. The model captures the experimental data in terms of macroscopic stress strain curves, evolution of stress and strain during holding, as well as evolution of the internal elastic strains. Model results indicate that the magnitude of the stress relaxed during strain holding is dependent on both, the magnitude of the flow stress and the spread of the resolved shear stress distribution. The magnitude of strain accumulated during stress holding is, on the other hand, dependent on the magnitude of the hardening rate and on the spread of the resolved shear stress distribution. Furthermore, the internal elastic strains are directly correlated with the stress state, and hence the stress relaxation during strain holds has a greater influence on the lattice strains than strain relaxation during stress holds.

Research Organization:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC52-06NA25396; FWP 06SCPE401
OSTI ID:
1329678
Alternate ID(s):
OSTI ID: 1252024
Report Number(s):
LA-UR-15-23052
Journal Information:
International Journal of Plasticity, Vol. 79, Issue C; ISSN 0749-6419
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 69 works
Citation information provided by
Web of Science

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Strength and ductility with {10͞11} — {10͞12} double twinning in a magnesium alloy journal April 2016
The effect of stress rate on ratchetting behavior of rolled AZ31B magnesium alloy at 393 K and room temperature journal May 2019
Validity of Crystal Plasticity Models Near Grain Boundaries: Contribution of Elastic Strain Measurements at Micron Scale journal August 2019