On the correlation between plastic strain and misorientation in polycrystalline body-centered-cubic microstructures with an emphasis on the grain size, loading history, and crystallographic orientation. (November 2021)

• Record Type: Journal Article
• Authors: Khademi, V.; Bieler, T.R.; Boehlert, C.J.
• Is Part Of: International journal of plasticity. Volume 146(2021)
• Publication Date: 2021-11
• Subjects: Misorientation -- Heterogenous plastic deformation -- Loading history -- Grain size -- Crystallographic orientation -- Polycrystalline materials -- In-situ SEM -- EBSD -- Titanium; Plasticity -- Periodicals; Plasticité -- Périodiques; Plasticity; Periodicals; 620.11233
• DOI: 10.1016/j.ijplas.2021.103084
• Languages: English
• ISSNs: 0749-6419

Abstract

Highlights: An empirical equation was proposed to estimate the level of misorientation dispersion at the grain scale as a function of grain size and plastic global strain. {100} and {110} orientations, with respect to tensile direction, exhibited the largest and smallest tendency for local orientation change, respectively. Large grains exhibited a greater misorientation level than the small grains, where the difference became more pronounced for larger grains with increased strain. The misorientation level is sensitive to the strain path, as the misorientation was higher for the interrupted tests compared with the monotonic tests. Abstract: The correlation between plastic strain and crystallographic misorientation, grain size, grain orientation, distance from grain boundary, and loading history were investigated experimentally and numerically for body-centered-cubic (BCC) polycrystalline microstructures based on a misorientation deviation (MD) approach. Nine monotonic tensile experiments were performed on two BCC titanium alloys inside a scanning electron microscope (SEM). The influence of reference orientation was explored both at the grain scale and at the mesoscale using electron backscattered diffraction (EBSD). The correlation between global plastic strain and the MD was quantified. The tendency for orientation change was quantified as a function of plastic strain and grain orientation for three crystallographic orientations (i.e., [100], [110], and [111]) with respect to tensile direction. The subpopulation of small grains exhibited a lower level of misorientation dispersion compared with larger grains, and this discrepancy became more pronounced at higher strains. An empirical equation was proposed to estimate the level of misorientation dispersion for individual grains as a function of grain size and global plastic strain level. Two interrupted in-situ SEM experiments were performed, and this resulted in a significantly increased misorientation compared with uninterrupted tests performed to similar plastic strain levels.