Title: Effect of loading path on grain misorientation and geometrically necessary dislocation density in polycrystalline aluminum under reciprocating shear

Abstract

Solid phase processing (SPP) is a promising alloy fabrication technique to produce fine and homogeneous grain structures for high-performance alloys. However, there is very limited modeling capability to understand and predict the grain refinement during SPP. In this work, the crystal plasticity theory was used to study elastic-plastic deformation in polycrystalline aluminums under large shear deformation. Two approaches, kernel averaged misorientation (KAM) and grain reference orientation deviation (GROD), were used to assess the grain misorientations. The geometrically necessary dislocation (GND) density was computed with the plastic strain rate. The deformation simulations were carried out under two loading conditions to investigate the effect of loading paths on the evolutions of grain misorientation and GND density. The results show that the regions with high misorientation and GND density first appear near grain boundaries. These regions then extend toward interior grains. The loading path affects dislocation system activation and dislocation recovery, hence dislocation evolution and misorientation. In conclusion, both two- and three-dimensional simulations showed that the spatial and temporal evolutions of GROD, KAM, and GND density in are closely correlated, which indicates they all can be used as criteria of grain refinement or recrystallization.

Authors:

Fu, Wenkai ^[1]; Li, Yulan ^[1]; Hu, Shenyang ^[1]; Sushko, Peter ^[1]; Mathaudhu, Suveen ^[2]

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+ Show Author Affiliations

1. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
2. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Colorado School of Mines, Golden, CO (United States)

Publication Date:

Mon Jan 24 00:00:00 EST 2022

Research Org.:

Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE Laboratory Directed Research and Development (LDRD) Program

OSTI Identifier:

2310938

Alternate Identifier(s):

OSTI ID: 1862578

Report Number(s):

PNNL-SA-163073
Journal ID: ISSN 0927-0256

Grant/Contract Number:  

AC05-76RL01830

Resource Type:

Accepted Manuscript

Journal Name:

Computational Materials Science

Additional Journal Information:

Journal Volume: 205; Journal ID: ISSN 0927-0256

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; 97 MATHEMATICS AND COMPUTING; Crystal plasticity; Shear deformation; GND density; Misorientation; Grain refinement