Investigation of grain boundary and orientation effects in polycrystalline metals by a dislocation-based crystal plasticity model

Abstract

Polycrystalline metal with well-designed grain structure exhibits different strength and ductility compared with the conventional macro scale materials. In the present study, the mechanisms of strain hardening and inhomogeneous deformation in polycrystals are analyzed by considering the interaction between dislocations and grain boundaries. Firstly, a dislocation density based crystal plasticity model is developed and then used to quantitatively study the grain size and orientation effects in polycrystals. With the decrease of grain size, the accumulation and interaction of dislocations are promoted in the grain, resulting in back-stress hardening. Simultaneously, two opposite effects of the inhomogeneity in grain orientation are obtained by evaluating the local Schmidt factors in each grain and their standard deviation. The findings highlight the effect of grain boundary on the strength and provide quantitative insight into the effect of grain orientation on ductility.

Strain rate-dependent hardening with dislocation-twin interaction of Fe–Mn–Al–C steel using crystal plasticity

“…A spatially inhomogeneous deformation field can be induced in polycrystalline deformation process to satisfy the compatibility between adjacent grains with different crystallographic orientations [41,42]. To investigate the intergranular deformation heterogeneity of TWIP steel, the distributions of four state variables at 0.001 s −1 with a true strain of 0.45 are presented in Figure 9.…”

Grain Boundary and Microstructural Characterization of Heat-Treated As-Rolled 2205 Duplex Stainless Steel

“…HAGB are created when the dislocation cores of low-angle tilt boundaries cross at an angle greater than 15° [22]. These limits have a haphazard, or more accurately, uneven structure [23]. Boundaries with a high orientation and a high density of coincidence locations relationship are referred to as SAGB [24].…”

Investigation on the Effects of Grain Boundary on Deformation Behavior of Bicrystalline Pillar by Crystal Plasticity Finite Element Method

“…Grain boundaries (GBs) have significant influence on the mechanical properties of polycrystalline materials by interacting with dislocations and other defects [1][2][3]. Therefore, the interactions between GBs and dislocations have attracted much attention for many decades [4][5][6][7][8][9].…”

“…Therefore, the interactions between GBs and dislocations have attracted much attention for many decades [4][5][6][7][8][9]. Due to the complexity, the detailed interaction between GB and dislocation has not been understood thoroughly to date [3,10,11]. However, it is well accepted that the interactions between dislocations and GBs have a close relationship with the GB misorientation angle [2,3].…”

“…Due to the complexity, the detailed interaction between GB and dislocation has not been understood thoroughly to date [3,10,11]. However, it is well accepted that the interactions between dislocations and GBs have a close relationship with the GB misorientation angle [2,3]. Dislocations trend to pile up at high-angle GBs (HAGBs) and pass through low-angle GBs (LAGBs) in popular opinion [12][13][14].…”