Comparison of dislocation density tensor fields derived from discrete dislocation dynamics and crystal plasticity simulations of torsion

Journal Article · Mon Feb 01 00:00:00 EST 2016 · Journal of Materials Science Research

DOI:https://doi.org/10.5539/jmsr.v5n4p44· OSTI ID:1252189

Jones, Reese E. ^[1]; Zimmerman, Jonathan A. ^[1]; Po, Giacomo ^[2]; Mandadapu, Kranthi ^[3]

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1. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
2. Univ. of California, Los Angeles, CA (United States)
3. Univ. of California, Berkeley, CA (United States)

Accurate simulation of the plastic deformation of ductile metals is important to the design of structures and components to performance and failure criteria. Many techniques exist that address the length scales relevant to deformation processes, including dislocation dynamics (DD), which models the interaction and evolution of discrete dislocation line segments, and crystal plasticity (CP), which incorporates the crystalline nature and restricted motion of dislocations into a higher scale continuous field framework. While these two methods are conceptually related, there have been only nominal efforts focused at the global material response that use DD-generated information to enhance the fidelity of CP models. To ascertain to what degree the predictions of CP are consistent with those of DD, we compare their global and microstructural response in a number of deformation modes. After using nominally homogeneous compression and shear deformation dislocation dynamics simulations to calibrate crystal plasticity ow rule parameters, we compare not only the system-level stress-strain response of prismatic wires in torsion but also the resulting geometrically necessary dislocation density fields. To establish a connection between explicit description of dislocations and the continuum assumed with crystal plasticity simulations we ascertain the minimum length-scale at which meaningful dislocation density fields appear. Furthermore, our results show that, for the case of torsion, that the two material models can produce comparable spatial dislocation density distributions.

• Research Organization: Sandia National Laboratories (SNL-CA), Livermore, CA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1252189
• Alternate ID(s): OSTI ID: 1415170
• Report Number(s): SAND--2016-0956J; 619083
• Journal Information: Journal of Materials Science Research, Journal Name: Journal of Materials Science Research Journal Issue: 4 Vol. 5; ISSN 1927-0585
• Publisher: Canadian Center of Science and Education
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
crystal plasticity
dislocation density field
dislocation dynamics