The five-parameter grain boundary curvature distribution in an austenitic and ferritic steel

Abstract

The distribution of grain boundary curvatures as a function of five independent crystallographic parameters is measured in an austenitic and a ferritic steel. Both local curvatures and integral mean curvatures are measured from three dimensional electron backscattered diffraction data. The method is first validated on ideal shapes. When applied to real microstructures, it is found that the grain boundary mean curvature varies with the boundary crystallography and is more sensitive to the grain boundary plane orientation than to the disorientation. The grain boundaries with the smallest curvatures also have low grain boundary energy and large relative areas. The results also show that the curvature is influenced by the grain size and by the number of nearest neighbors. For austenite, when the number of faces on a grain is equal to the average number of faces of its neighbors, it has zero integral mean curvature.

Grain boundary curvatures in polycrystalline SrTiO3: Dependence on grain size, topology, and crystallography

“…[16,32]. Because of the terrace-step geometry of the interface created by the cube-shaped voxels, these interfaces are poor imitations of real grain boundaries, which are presumed to be smooth on a micron length scale.…”

“…While this might be a reasonable approximation in some cases, it often fails to predict the motions of specific boundaries. 16 The method has been applied to two ferrous alloys and it was found that the curvature varies strongly as a function of the grain boundary plane orientation. In most work, H is assumed to be the inverse of the mean spherical equivalent grain radius.…”

“…With the emergence of three-dimensional microscopic techniques and simulations, it has become possible to locally measure curvature within voxelized microstructures [10][11][12][13][14][15] and a technique that can be used to measure local grain boundary curvature and correlate it to the crystallography of the grain boundary has recently been reported. 16 The method has been applied to two ferrous alloys and it was found that the curvature varies strongly as a function of the grain boundary plane orientation. Here, we apply the same technique to a ceramic (SrTiO 3 ) and explore in more detail the correlations among the grain boundary relative area, energy, and curvature.…”

Digital/virtual microstructures in application to metals engineering – A review

“…Obtained 3D model was then used to investigate microstructure behavior under various deformation conditions: uniaxial stretch, plane strain or uniaxial tension. The 3D EBSD was also recently used in other works focusing on metallic materials [42][43][44]. Similar research, but based just on the FIB/SEM was performed in [45], where authors used the FIB to reconstruct microstructure of porous metallic material or in [46] where primary carbides in the NiTa-Al-Cr-C alloy were investigated.…”

Analysis of the Grain Size Evolution for Ferrite Formation in Fe-C-Mn Steels Using a 3D Model Under a Mixed-Mode Interface Condition

“…[1][2][3][4][5][6] Their mechanical properties, which are controlled by their microstructure, can be tuned relatively easily by thermomechanical processing. Ferrite is the first transformation product that forms during cooling as a result of austenite decomposition.…”