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Title: Monitoring evolution of stress in individual grains and twins in a magnesium alloy aggregate

Abstract

Crystallographic twinning is a strain accommodation mechanism extensively observed in low-symmetry crystals. In hexagonal metals (HCP), twinning transformation results in abrupt crystallographic reorientation of grain domains, and strongly affects the mechanical response, texture evolution, plastic formability and internal stress evolution. Recent fundamental advances in constitutive descriptions ofHCP's indicate the need for a basic characterization oftwinning mechanisms. Here we use the emerging technique of 3DXRD [9-12], for the first time, to in-situ monitor the twin nucleation and growth in individual grains inside the bulk of a magnesium alloy aggregate. At the same time, we accomplish the first direct measurement of the evolving triaxial stress states in both the parent grain and its twin. We show that the stress state of the twin is radically different from that of the parent and interpret the three-dimensional response in the light of the constraints placed on the parent and the twin by the surrounding polycrystalline medium.

Authors:
 [1];  [1];  [1];  [1];  [2];  [3]
  1. Los Alamos National Laboratory
  2. LLNL
  3. ANL
Publication Date:
Research Org.:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
960690
Report Number(s):
LA-UR-08-05952; LA-UR-08-5952
TRN: US201008%%623
DOE Contract Number:  
AC52-06NA25396
Resource Type:
Journal Article
Journal Name:
Nature Materials
Additional Journal Information:
Journal Name: Nature Materials
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CRYSTALS; CRYSTALLOGRAPHY; GROWTH; MAGNESIUM ALLOYS; METALS; MONITORING; NUCLEATION; PLASTICITY; STRAINS; TEXTURE; TRANSFORMATIONS; TWINNING

Citation Formats

Clausen, Bjorn, Aydiner, Cahit C, Tome, Carlos N, Brown, Donald W, Bernier, Joel V, and Lienert, Ulrich. Monitoring evolution of stress in individual grains and twins in a magnesium alloy aggregate. United States: N. p., 2008. Web.
Clausen, Bjorn, Aydiner, Cahit C, Tome, Carlos N, Brown, Donald W, Bernier, Joel V, & Lienert, Ulrich. Monitoring evolution of stress in individual grains and twins in a magnesium alloy aggregate. United States.
Clausen, Bjorn, Aydiner, Cahit C, Tome, Carlos N, Brown, Donald W, Bernier, Joel V, and Lienert, Ulrich. 2008. "Monitoring evolution of stress in individual grains and twins in a magnesium alloy aggregate". United States. https://www.osti.gov/servlets/purl/960690.
@article{osti_960690,
title = {Monitoring evolution of stress in individual grains and twins in a magnesium alloy aggregate},
author = {Clausen, Bjorn and Aydiner, Cahit C and Tome, Carlos N and Brown, Donald W and Bernier, Joel V and Lienert, Ulrich},
abstractNote = {Crystallographic twinning is a strain accommodation mechanism extensively observed in low-symmetry crystals. In hexagonal metals (HCP), twinning transformation results in abrupt crystallographic reorientation of grain domains, and strongly affects the mechanical response, texture evolution, plastic formability and internal stress evolution. Recent fundamental advances in constitutive descriptions ofHCP's indicate the need for a basic characterization oftwinning mechanisms. Here we use the emerging technique of 3DXRD [9-12], for the first time, to in-situ monitor the twin nucleation and growth in individual grains inside the bulk of a magnesium alloy aggregate. At the same time, we accomplish the first direct measurement of the evolving triaxial stress states in both the parent grain and its twin. We show that the stress state of the twin is radically different from that of the parent and interpret the three-dimensional response in the light of the constraints placed on the parent and the twin by the surrounding polycrystalline medium.},
doi = {},
url = {https://www.osti.gov/biblio/960690}, journal = {Nature Materials},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 2008},
month = {Tue Jan 01 00:00:00 EST 2008}
}