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Gregory S. Rohrer - One of the best experts on this subject based on the ideXlab platform.
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five parameter intervariant Boundary characterization of martensite in commercially pure titanium
Acta Materialia, 2018Co-Authors: Ehsan Farabi, Gregory S. Rohrer, Peter Hodgson, Hossein BeladiAbstract:Abstract The intervariant Boundary characteristics of a commercially pure Ti microstructure formed by the β → α martensitic phase transformation were described according to the crystallography of the displacive transformation and the Boundary Plane orientation. The martensitic transformation created a microstructure whose grain Boundary misorientation angle distribution had four distinct peaks that were consistent with the misorientations between the variants produced by the Burgers orientation relationship. Interestingly, about 60% of population corresponded to 60°/ [ 11 2 ¯ 0 ] intervariant boundaries. Three-variant clusters with a triangular morphology were observed frequently. This configuration is consistent with the phenomenological theory of martensite, which predicts that these clusters, separated by 60°/ [ 11 2 ¯ 0 ] boundaries, have a lower transformation strain than other possible variant cluster arrangements. Other intervariant boundaries resulted from the impingement of different combinations of distinct three-variant clusters. The five-parameter Boundary analysis revealed a strong anisotropy in the Plane orientation distribution, showing that boundaries have a tendency to terminate on prismatic { h k i 0 } and pyramidal { 10 1 ¯ 1 } Planes, when misorientation was ignored. The dominant 60°/ [ 11 2 ¯ 0 ] intervariant boundaries had symmetric tilt ( 1 ¯ 101 ) Boundary Planes, which are a low energy configuration.
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the five parameter grain Boundary curvature distribution in an austenitic and ferritic steel
Acta Materialia, 2017Co-Authors: Xiaoting Zhong, Hossein Beladi, D J Rowenhorst, Gregory S. RohrerAbstract: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.
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grain Boundary energies in body centered cubic metals
Acta Materialia, 2015Co-Authors: Anthony D Rollett, Sutatch Ratanaphan, David L Olmsted, Vasily V Bulatov, Elizabeth A Holm, Gregory S. RohrerAbstract:Abstract Atomistic simulations using the embedded atom method were employed to compute the energies of 408 distinct grain boundaries in bcc Fe and Mo. This set includes grain boundaries that have tilt, twist, and mixed character and coincidence site lattices ranging from Σ3 to Σ323. The results show that grain Boundary energies in Fe and Mo are influenced more by the grain Boundary Plane orientation than by the lattice misorientation or lattice coincidence. Furthermore, grain boundaries with (1 1 0) Planes on both sides of the Boundary have low energies, regardless of the misorientation angle or geometric character. Grain boundaries of the same type in Fe and Mo have strongly correlated energies that scale with the ratio of the cohesive energies of the two metals.
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the equilibrium crystal shape of strontium titanate and its relationship to the grain Boundary Plane distribution
Acta Materialia, 2015Co-Authors: Wolfgang Rheinheimer, Gregory S. Rohrer, John E Blendell, Michael Baurer, Harry Chien, Carol A Handwerker, Michael J. HoffmannAbstract:In this study, the equilibrium crystal shape (ECS) of a model system, strontium titanate, is compared with the grain Boundary Plane distribution (GBPD) as a function of temperature. Strontium titanate has a pronounced surface energy anisotropy and a grain growth anomaly, with the grain growth rate decreasing by orders of magnitude with increasing temperature. The ECS was determined from the shape of small intragranular pores and the GBPD was determined from orientation measurements on surfaces, with the relative areas of grain Boundary Planes in a polycrystal correlated to the surface energy of both adjacent crystal Planes. The grain Boundary energy has been previously proposed to be the sum of the surface energy of the adjacent grains less a binding energy that is assumed to be constant. While much experimental evidence exists for this assumption at a fixed temperature, the influence of temperature is not known. While the anisotropy of the ECS was found to decrease with temperature, the anisotropy of the GBPD increased with temperature. These findings indicate that changes in the binding energy with temperature must be considered, as the binding energy links the surface energy to the grain Boundary energy. The results are discussed with respect to the grain growth anomaly of strontium titanate, in which the grain growth decreases with increasing temperature.
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the five parameter grain Boundary character and energy distributions of a fully austenitic high manganese steel using three dimensional data
Acta Materialia, 2014Co-Authors: Hossein Beladi, N T Nuhfer, Gregory S. RohrerAbstract:Abstract The three-dimensional interfacial grain Boundary network in a fully austenitic high-manganese steel was studied as a function of all five macroscopic crystallographic parameters (i.e. lattice misorientation and grain Boundary Plane normal) using electron backscattering diffraction mapping in conjunction with focused ion beam serial sectioning. The relative grain Boundary area and energy distributions were strongly influenced by both the grain Boundary Plane orientation and the lattice misorientation. Grain boundaries terminated by (1 1 1) Plane orientations revealed relatively higher populations and lower energies compared with other boundaries. The most frequently observed grain boundaries were {1 1 1} symmetric twist boundaries with the Σ3 misorientation, which also had the lowest energy. On average, the relative areas of different grain Boundary types were inversely correlated to their energies. A comparison between the current result and previously reported observations (e.g. high-purity Ni) revealed that polycrystals with the same atomic structure (e.g. face-centered cubic) have very similar grain Boundary character and energy distributions.
Valerie Randle - One of the best experts on this subject based on the ideXlab platform.
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grain Boundary Plane distributions and single step versus multiple step grain Boundary engineering
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Valerie Randle, Richard A L JonesAbstract:Abstract The ‘five-parameter’ (i.e. both misorientation and grain Boundary Plane) distribution in type 304 austenitic stainless steel has been measured and evaluated for an ‘as-received’ (AR) specimen and specimens undergoing both single-step grain Boundary engineering processing (SSGBE) and multiple-step grain Boundary engineering processing (MSGBE) comprising three iterations. The results showed that the fundamental requirement for twinning-related GBE is to maximise concomitantly the proportion of both Σ3 and Σ9 boundaries, which in turn supports the development of special Planes in the grain Boundary network. 〈1 1 0〉 and 〈1 1 1〉 tilt and twist boundaries play a key role in the formation of ‘special’ grain Boundary Planes. MSGBE added increased proportions of Σ3 boundaries and resulted in development of different characteristics in the Planes distribution compared to SSGBE. These modifications are likely to result in improved grain Boundary properties after MSGBE compared to SSGBE.
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carbide precipitation and grain Boundary Plane selection in overaged type 316 austenitic stainless steel
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: Richard A L Jones, Valerie Randle, G T OwenAbstract:Abstract The misorientation and the grain Boundary Plane distribution in an overaged type 316 specimen have been measured, coupled with observations of M 23 C 6 precipitation. There were many grain Boundary Planes on {1 1 1} in the random Boundary population, notably {1 1 1} twist boundaries and 〈1 1 0〉 asymmetric tilt boundaries having one {1 1 1} Plane. Precipitation was selective with respect to Boundary Plane type. Only coherent twins were immune to precipitation. For both random boundaries and incoherent Σ3s, boundaries which were not on {1 1 1} had more precipitation than did {1 1 1} twist boundaries. The enhanced proportion of {1 1 1} twist boundaries promoted plate-like carbide coarsening, which is associated with reduced cavity nucleation. A microstructure having a high proportion of {1 1 1} Boundary Planes, especially {1 1 1} twists, is therefore beneficial. It is suggested that the long age allowed a ‘fine tuning’ effect at interfaces whereby they approached energy minima.
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five parameter grain Boundary distribution of commercially grain Boundary engineered nickel and copper
Acta Materialia, 2008Co-Authors: Valerie Randle, Gregory S. Rohrer, Herbert M Miller, M Coleman, G T OwenAbstract:Abstract The five-parameter grain Boundary distributions of grain Boundary engineered nickel and copper specimens have been analyzed in detail. The relative areas of {1 1 1} Planes in the entire population did not increase as a result of grain Boundary engineering (GBE) and, in the Σ3-excluded population, decreased after GBE. This decrease occurred because the majority of the newly generated Σ3 grain boundaries were not coherent twins with {1 1 1} grain Boundary Plane orientations. GBE increased the proportion of Σ3 Boundary length that was vicinal-to-{1 1 1} and the proportion of asymmetrical 〈1 1 0〉 tilt boundaries. There was a clear propensity for selection of particular Planes or Plane combinations which were associated with low energy. These Plane types were analyzed in some detail, and it was shown that many of these boundaries were asymmetrical tilts comprising (or vicinal to) at least one low-index Plane.
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special boundaries and grain Boundary Plane engineering
Scripta Materialia, 2006Co-Authors: Valerie RandleAbstract:Abstract The definition of a ‘special’ grain Boundary is addressed. A definition based on the presence of at least one low-index Plane at a Boundary is germane to grain Boundary engineering. Experimental evidence is demonstrated. From the emphasis on Boundary Planes, ‘grain Boundary Plane engineering’ should be promoted.
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a comparison between three dimensional and two dimensional grain Boundary Plane analysis
Ultramicroscopy, 2002Co-Authors: Valerie Randle, Helen DaviesAbstract:An EBSD-based methodology for assessment of grain Boundary Planes, in particular Σ3 boundaries in face-centred cubic materials, has recently been devised. The method is based on trace analysis in a single, two-dimensional section rather than the more arduous three-dimensional method. The paper reports a data set of grain Boundary Planes in alpha-brass, mainly Σ3s, which have been analysed using both methods so that they can be compared and a recommendation made about the usefulness of the new method. It is shown that the new, two-dimensional method is a valuable tool in the analysis of grain Boundary geometry, especially when used in conjunction with v/vm, a parameter for assessing the proximity to the misorientation reference structure.
Anthony D Rollett - One of the best experts on this subject based on the ideXlab platform.
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grain Boundary energies in body centered cubic metals
Acta Materialia, 2015Co-Authors: Anthony D Rollett, Sutatch Ratanaphan, David L Olmsted, Vasily V Bulatov, Elizabeth A Holm, Gregory S. RohrerAbstract:Abstract Atomistic simulations using the embedded atom method were employed to compute the energies of 408 distinct grain boundaries in bcc Fe and Mo. This set includes grain boundaries that have tilt, twist, and mixed character and coincidence site lattices ranging from Σ3 to Σ323. The results show that grain Boundary energies in Fe and Mo are influenced more by the grain Boundary Plane orientation than by the lattice misorientation or lattice coincidence. Furthermore, grain boundaries with (1 1 0) Planes on both sides of the Boundary have low energies, regardless of the misorientation angle or geometric character. Grain boundaries of the same type in Fe and Mo have strongly correlated energies that scale with the ratio of the cohesive energies of the two metals.
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the distribution of intervariant crystallographic Planes in a lath martensite using five macroscopic parameters
Acta Materialia, 2014Co-Authors: Hossein Beladi, Anthony D Rollett, Gregory S. Rohrer, Vahid TariAbstract:Abstract Electron backscatter diffraction analysis was employed to compute the closest orientation relationship and the distribution of intervariant Boundary character in a lath martensitic microstructure. The misorientations were close to the Kurdjumov–Sachs orientation relationship. The intervariant crystallographic Plane distribution exhibited a relatively high anisotropy with a tendency for the lath interfaces to terminate on (1 1 0) Planes. This results from the crystallographic constraints associated with the shear transformation rather than a low energy interface configuration. The lath martensite habit Plane was determined to be mostly (1 1 0) or near (1 1 0). The relative populations of boundaries with [1 1 1] and [1 1 0] misorientations were greater than other high index misorientations, mostly characterized as (1 1 0) symmetric tilt and (1 1 0) twist Boundary types, respectively. Analysis with homology metrics of the connectivity in the lath martensitic microstructure revealed the connectivity dominated by population of misorientation angle and Boundary Plane type.
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grain Boundary character distribution of nanocrystalline cu thin films using stereological analysis of transmission electron microscope orientation maps
Microscopy and Microanalysis, 2013Co-Authors: Amith Darbal, Gregory S. Rohrer, K J Ganesh, Xiaoming Liu, Sukbin Lee, Jon Ledonne, T Sun, B Yao, Andrew P Warren, Anthony D RollettAbstract:Stereological analysis has been coupled with transmission electron microscope (TEM) orientation mapping to investigate the grain Boundary character distribution in nanocrystalline copper thin films. The use of the nanosized (<5 nm) beam in the TEM for collecting spot diffraction patterns renders an order of magnitude improvement in spatial resolution compared to the analysis of electron backscatter diffraction patterns in the scanning electron microscope. Electron beam precession is used to reduce dynamical effects and increase the reliability of orientation solutions. The misorientation distribution function shows a strong misorientation texture with a peak at 60°/[111], corresponding to the Σ3 misorientation. The grain Boundary Plane distribution shows {111} as the most frequently occurring Plane, indicating a significant population of coherent twin boundaries. This study demonstrates the use of nanoscale orientation mapping in the TEM to quantify the five-parameter grain Boundary distribution in nanocrystalline materials.
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grain Boundary character distribution of nanocrystalline cu thin films using stereological analysis of transmission electron microscope orientation maps
Microscopy and Microanalysis, 2013Co-Authors: Amith Darbal, Gregory S. Rohrer, Anthony D Rollett, K J Ganesh, Jon Ledonne, Andrew P Warren, Paulo J Ferreira, K R Coffey, K BarmakAbstract:: Stereological analysis has been coupled with transmission electron microscope (TEM) orientation mapping to investigate the grain Boundary character distribution in nanocrystalline copper thin films. The use of the nanosized (<5 nm) beam in the TEM for collecting spot diffraction patterns renders an order of magnitude improvement in spatial resolution compared to the analysis of electron backscatter diffraction patterns in the scanning electron microscope. Electron beam precession is used to reduce dynamical effects and increase the reliability of orientation solutions. The misorientation distribution function shows a strong misorientation texture with a peak at 60°/[111], corresponding to the Σ3 misorientation. The grain Boundary Plane distribution shows {111} as the most frequently occurring Plane, indicating a significant population of coherent twin boundaries. This study demonstrates the use of nanoscale orientation mapping in the TEM to quantify the five-parameter grain Boundary distribution in nanocrystalline materials.
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effect of anisotropic grain Boundary properties on grain Boundary Plane distributions during grain growth
Scripta Materialia, 2005Co-Authors: Jason Gruber, Gregory S. Rohrer, Denise C George, Andrew P Kuprat, Anthony D RollettAbstract:Abstract The effects of anisotropic grain Boundary properties on the evolution of Boundary Plane distributions were studied using three-dimensional finite element simulations of normal grain growth. The distribution of Boundary Planes was affected by energy anisotropy whereas no effect was observed for comparatively larger mobility anisotropy.
Yuichi Ikuhara - One of the best experts on this subject based on the ideXlab platform.
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structure of the basal edge dislocation in zno
Crystals, 2018Co-Authors: Atsutomo Nakamura, Ryota Nagahara, Yuho Furushima, Yu Oshima, Tatsuya Yokoi, Eita Tochigi, Yuichi Ikuhara, Katsuyuki MatsunagaAbstract:Basal dislocations having a Burgers vector of 1/3 in zinc oxide (ZnO) with the wurtzite structure are known to strongly affect physical properties in bulk. However, the core structure of the basal dislocation remains unclear. In the present study, ZnO bicrystals with a {2 1 ¯ 1 ¯ 0}/ 2° low-angle tilt grain Boundary were fabricated by diffusion bonding. The resultant dislocation core structure was observed by using scanning transmission electron microscopy (STEM) at an atomic resolution. It was found that a basal edge dislocation in α-type is dissociated into two partial dislocations on the (0001) Plane with a separation distance of 1.5 nm, indicating the glide dissociation. The Burgers vectors of the two partial dislocations were 1/3 and 1/3 , and the stacking fault between the two partials on the (0001) Plane has a formation energy of 0.14 J/m2. Although the bicrystals have a Boundary Plane of {2 1 ¯ 1 ¯ 0}, the Boundary basal dislocations do not exhibit dissociation along the Boundary Plane, but along the (0001) Plane perpendicular to the Boundary Plane. From DFT calculations, the stacking fault on the (0001) Plane was found to be much more stable than that on {2 1 ¯ 1 ¯ 0}. Such an extremely low energy of the (0001) stacking fault can realize transverse dissociation of the basal dislocation of ZnO.
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structure of the basal edge dislocation in zno
Crystals, 2018Co-Authors: Atsutomo Nakamura, Ryota Nagahara, Yuho Furushima, Yu Oshima, Tatsuya Yokoi, Eita Tochigi, Yuichi Ikuhara, Katsuyuki MatsunagaAbstract:Basal dislocations having a Burgers vector of 1/3 in zinc oxide (ZnO) with the wurtzite structure are known to strongly affect physical properties in bulk. However, the core structure of the basal dislocation remains unclear. In the present study, ZnO bicrystals with a {2 1 ¯ 1 ¯ 0}/ 2° low-angle tilt grain Boundary were fabricated by diffusion bonding. The resultant dislocation core structure was observed by using scanning transmission electron microscopy (STEM) at an atomic resolution. It was found that a basal edge dislocation in α-type is dissociated into two partial dislocations on the (0001) Plane with a separation distance of 1.5 nm, indicating the glide dissociation. The Burgers vectors of the two partial dislocations were 1/3 and 1/3 , and the stacking fault between the two partials on the (0001) Plane has a formation energy of 0.14 J/m2. Although the bicrystals have a Boundary Plane of {2 1 ¯ 1 ¯ 0}, the Boundary basal dislocations do not exhibit dissociation along the Boundary Plane, but along the (0001) Plane perpendicular to the Boundary Plane. From DFT calculations, the stacking fault on the (0001) Plane was found to be much more stable than that on {2 1 ¯ 1 ¯ 0}. Such an extremely low energy of the (0001) stacking fault can realize transverse dissociation of the basal dislocation of ZnO.
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grain Boundary Plane effect on pr segregation site in zno σ13 0001 symmetric tilt grain boundaries
Journal of the American Ceramic Society, 2015Co-Authors: Ji Young Roh, Yuichi Ikuhara, Yukio SatoAbstract:As grain Boundary (GB) and GB segregation often have significant impact on various properties of polycrystalline materials, their atomic structures as well as the location of segregated dopant should be intensively investigated. We have thus reported several papers about segregation of Pr (praseodymium) in ZnO (zinc oxide) GBs for case study. In this study, we study the atomic structure of Pr-doped ZnO [0001]/(134¯0) Σ13 symmetric tilt GB, and the results are compared with that for the (257¯0) GB [Sato et al., Phys. Rev. B, 87,140101 (2013)]. Although atomic arrangements of these GBs can be characterized using the same kinds of structural units (SUs), Pr segregation sites relative to the SU vary with GBs. It is suggested that change in strain distribution for different GBs would cause the variation in the segregation sites and Pr would prefer the Zn site of locally highest tension.
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haadf stem observations of a σ13 grain Boundary in α al2o3 from two orthogonal directions
Philosophical Magazine Letters, 2010Co-Authors: Shinya Azuma, Naoya Shibata, S D Findlay, Teruyasu Mizoguchi, T Yamamoto, Yuichi IkuharaAbstract:Atomic structure of a Σ = 13, grain Boundary in α-Al2O3 was directly observed by aberration-corrected Z-contrast scanning transmission electron microscopy. Combining observations from two orthogonal directions parallel to the grain Boundary Plane , the three-dimensional atomic configuration of the grain Boundary core region can be determined, and proves to be in a good agreement with the stable Boundary structure predicted by first-principles calculations.
Hossein Beladi - One of the best experts on this subject based on the ideXlab platform.
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five parameter intervariant Boundary characterization of martensite in commercially pure titanium
Acta Materialia, 2018Co-Authors: Ehsan Farabi, Gregory S. Rohrer, Peter Hodgson, Hossein BeladiAbstract:Abstract The intervariant Boundary characteristics of a commercially pure Ti microstructure formed by the β → α martensitic phase transformation were described according to the crystallography of the displacive transformation and the Boundary Plane orientation. The martensitic transformation created a microstructure whose grain Boundary misorientation angle distribution had four distinct peaks that were consistent with the misorientations between the variants produced by the Burgers orientation relationship. Interestingly, about 60% of population corresponded to 60°/ [ 11 2 ¯ 0 ] intervariant boundaries. Three-variant clusters with a triangular morphology were observed frequently. This configuration is consistent with the phenomenological theory of martensite, which predicts that these clusters, separated by 60°/ [ 11 2 ¯ 0 ] boundaries, have a lower transformation strain than other possible variant cluster arrangements. Other intervariant boundaries resulted from the impingement of different combinations of distinct three-variant clusters. The five-parameter Boundary analysis revealed a strong anisotropy in the Plane orientation distribution, showing that boundaries have a tendency to terminate on prismatic { h k i 0 } and pyramidal { 10 1 ¯ 1 } Planes, when misorientation was ignored. The dominant 60°/ [ 11 2 ¯ 0 ] intervariant boundaries had symmetric tilt ( 1 ¯ 101 ) Boundary Planes, which are a low energy configuration.
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the five parameter grain Boundary curvature distribution in an austenitic and ferritic steel
Acta Materialia, 2017Co-Authors: Xiaoting Zhong, Hossein Beladi, D J Rowenhorst, Gregory S. RohrerAbstract: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.
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the five parameter grain Boundary character and energy distributions of a fully austenitic high manganese steel using three dimensional data
Acta Materialia, 2014Co-Authors: Hossein Beladi, N T Nuhfer, Gregory S. RohrerAbstract:Abstract The three-dimensional interfacial grain Boundary network in a fully austenitic high-manganese steel was studied as a function of all five macroscopic crystallographic parameters (i.e. lattice misorientation and grain Boundary Plane normal) using electron backscattering diffraction mapping in conjunction with focused ion beam serial sectioning. The relative grain Boundary area and energy distributions were strongly influenced by both the grain Boundary Plane orientation and the lattice misorientation. Grain boundaries terminated by (1 1 1) Plane orientations revealed relatively higher populations and lower energies compared with other boundaries. The most frequently observed grain boundaries were {1 1 1} symmetric twist boundaries with the Σ3 misorientation, which also had the lowest energy. On average, the relative areas of different grain Boundary types were inversely correlated to their energies. A comparison between the current result and previously reported observations (e.g. high-purity Ni) revealed that polycrystals with the same atomic structure (e.g. face-centered cubic) have very similar grain Boundary character and energy distributions.
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the distribution of intervariant crystallographic Planes in a lath martensite using five macroscopic parameters
Acta Materialia, 2014Co-Authors: Hossein Beladi, Anthony D Rollett, Gregory S. Rohrer, Vahid TariAbstract:Abstract Electron backscatter diffraction analysis was employed to compute the closest orientation relationship and the distribution of intervariant Boundary character in a lath martensitic microstructure. The misorientations were close to the Kurdjumov–Sachs orientation relationship. The intervariant crystallographic Plane distribution exhibited a relatively high anisotropy with a tendency for the lath interfaces to terminate on (1 1 0) Planes. This results from the crystallographic constraints associated with the shear transformation rather than a low energy interface configuration. The lath martensite habit Plane was determined to be mostly (1 1 0) or near (1 1 0). The relative populations of boundaries with [1 1 1] and [1 1 0] misorientations were greater than other high index misorientations, mostly characterized as (1 1 0) symmetric tilt and (1 1 0) twist Boundary types, respectively. Analysis with homology metrics of the connectivity in the lath martensitic microstructure revealed the connectivity dominated by population of misorientation angle and Boundary Plane type.
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the relative grain Boundary area and energy distributions in a ferritic steel determined from three dimensional electron backscatter diffraction maps
Acta Materialia, 2013Co-Authors: Hossein Beladi, Gregory S. RohrerAbstract:Abstract The relative grain Boundary area and energy distributions of a ferritic steel were characterized as a function of lattice misorientation and Boundary Plane orientation using focused ion beam serial sectioning combined with electron backscatter diffraction. The grain Boundary energy and population depended on both the grain Boundary Plane orientation and lattice misorientation. When misorientation was ignored grain Boundary Planes with the (1 1 1) orientation had the minimum energy and the largest relative areas. The most commonly observed boundaries were {1 1 2} symmetric tilt boundaries with the Σ3 misorientation; this Boundary also had a low energy. On average there was a strong inverse correlation between the relative areas of different types of grain boundaries and the relative grain Boundary energies.