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Title: Modeling the strength and ductility of magnesium alloys containing nanotwins

Abstract

ABSTRACT Magnesium alloys have been receiving much attention recently as potential lightweight alternatives to steel for automotive and other applications, but the poor formability of these alloys at low temperatures has limited their widespread adoption for automotive applications. Recent work with face centered cubic (FCC) materials has shown that introduction of twins at the nanometer scale in ultra-fine grained FCC polycrystals can provide significant increase in strength with a simultaneous improvement in ductility. This objective of this work is to explore the feasibility of extending this concept to hexagonal close packed (HCP) materials, with particular focus on using this approach to increase both strength and ductility of magnesium alloys. A crystal plasticity based finite element (CPFE) model is used to study the effect of varying the crystallographic texture and the spacing between the nanoscale twins on the strength and ductility of HCP polycrystals. Deformation of the material is assumed to occur by crystallographic slip, and in addition to the basal and prismatic slip systems, slip is also assumed to occur on the {1 0$$\bar 1$$1} planes that are associated with compression twins in these materials. The slip system strength of the pyramidal systems containing the nanotwins is assumed to bemore » much lower than the strength of the other systems, which is assumed to scale with the spacing between the nanotwins. The CPFE model is used to compute the stress-strain response for different microstrucrutral parameters, and a criterion based on a critical slip system shear strain and a critical hydrostatic stress is used to compute the limiting strength and ductility, with the ultimate goal of identifying the texture and nanotwin spacing that can lead to the optimum values for these parameters.« less

Authors:
 [1];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computer Science and Mathematics Div.
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1567665
Resource Type:
Journal Article
Journal Name:
Materials Research Society Symposia Proceedings
Additional Journal Information:
Journal Volume: 1513; Conference: Symposium GG – Mechanical Behavior of Metallic Nanostructured Materials; Journal ID: ISSN 0272-9172
Country of Publication:
United States
Language:
English

Citation Formats

Gorti, S. B., and Radhakrishnan, B. Modeling the strength and ductility of magnesium alloys containing nanotwins. United States: N. p., 2013. Web. doi:10.1557/opl.2013.499.
Gorti, S. B., & Radhakrishnan, B. Modeling the strength and ductility of magnesium alloys containing nanotwins. United States. https://doi.org/10.1557/opl.2013.499
Gorti, S. B., and Radhakrishnan, B. 2013. "Modeling the strength and ductility of magnesium alloys containing nanotwins". United States. https://doi.org/10.1557/opl.2013.499.
@article{osti_1567665,
title = {Modeling the strength and ductility of magnesium alloys containing nanotwins},
author = {Gorti, S. B. and Radhakrishnan, B.},
abstractNote = {ABSTRACT Magnesium alloys have been receiving much attention recently as potential lightweight alternatives to steel for automotive and other applications, but the poor formability of these alloys at low temperatures has limited their widespread adoption for automotive applications. Recent work with face centered cubic (FCC) materials has shown that introduction of twins at the nanometer scale in ultra-fine grained FCC polycrystals can provide significant increase in strength with a simultaneous improvement in ductility. This objective of this work is to explore the feasibility of extending this concept to hexagonal close packed (HCP) materials, with particular focus on using this approach to increase both strength and ductility of magnesium alloys. A crystal plasticity based finite element (CPFE) model is used to study the effect of varying the crystallographic texture and the spacing between the nanoscale twins on the strength and ductility of HCP polycrystals. Deformation of the material is assumed to occur by crystallographic slip, and in addition to the basal and prismatic slip systems, slip is also assumed to occur on the {1 0$\bar 1$1} planes that are associated with compression twins in these materials. The slip system strength of the pyramidal systems containing the nanotwins is assumed to be much lower than the strength of the other systems, which is assumed to scale with the spacing between the nanotwins. The CPFE model is used to compute the stress-strain response for different microstrucrutral parameters, and a criterion based on a critical slip system shear strain and a critical hydrostatic stress is used to compute the limiting strength and ductility, with the ultimate goal of identifying the texture and nanotwin spacing that can lead to the optimum values for these parameters.},
doi = {10.1557/opl.2013.499},
url = {https://www.osti.gov/biblio/1567665}, journal = {Materials Research Society Symposia Proceedings},
issn = {0272-9172},
number = ,
volume = 1513,
place = {United States},
year = {2013},
month = {1}
}

Works referenced in this record:

Simulation of texture evolution and macroscopic properties in Mg alloys using the crystal plasticity finite element method
journal, February 2010


Simulation of polycrystal deformation with grain and grain boundary effects
journal, September 2011


Finite element simulations of cold deformation at the mesoscale
journal, September 1998


Modeling the effect of microstructural features on the nucleation of creep cavities
journal, October 2008


Strength, strain-rate sensitivity and ductility of copper with nanoscale twins
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Deformation twinning in a nanocrystalline hcp Mg alloy
journal, February 2011