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

• Published in: Computational materials science Vol. 205; no. C; p. 111221
• Main Authors: Fu, Wenkai, Li, Yulan, Hu, Shenyang, Sushko, Peter, Mathaudhu, Suveen
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2022; Elsevier
• Subjects: Crystal plasticity; GND density; Grain refinement; Misorientation; Shear deformation; GND density; Crystal plasticity; Misorientation; Grain refinement; Shear deformation
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2022.111221

Our crystal plasticity simulations (both 2D and 3D) showed loading path significantly affects plastic deformation accumulation. Reciprocating shear through path 2 caused larger grain misorientation and geometrically necessary dislocation density than through path 1. [Display omitted] •Crystal plasticity of finite strain was used to simulate shear deformation of polycrystalline aluminum under cyclic load.•The spatiotemporal evolutions of GND density and misorientations (both KAM andGROD) were calculated.•The large GND density, KAM, and GROD first took place near the grain boundary then propagated toward inside of the grain.•Cyclic shear strain in two sides (with strain of −30%⇌0 ⇌ 30%) led to greater GND density, KAM, and GROD than in one side (0 ⇌ 30%).•The GND density, KAM, and GROD are correlated, and all can be used as criteria of grain refinement or recrystallization. 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 plastic deformation accumulation and recovery, hence dislocation evolution and misorientation. Both two- and three-dimensional simulations showed that the spatial and temporal evolutions of GROD, KAM, and GND density are closely correlated, which indicates they all can be used as criteria of grain refinement or recrystallization, the essential information for grain refinement simulations.