EBSD Characteristics of HSLA100 Steel Quenched in the 2-Phase Region

2011 ◽  
Vol 415-417 ◽  
pp. 901-906
Author(s):  
Xiang Yan ◽  
Fu Xing Yin ◽  
Gui Feng Zhou ◽  
W. Chen
Keyword(s):  
Grain Boundaries ◽  
Electron Backscatter Diffraction ◽  
Heating Temperature ◽  
Lath Martensite ◽  
Transformation Products ◽  
Phase Region ◽  
High Angle ◽  
Quenching Temperature ◽  
Grain Boundary Characteristics ◽  
Boundary Characteristics

The grain and grain boundary characteristics of HSLA100 steel quenched in the 2-phase region were investigated by electron backscatter diffraction (EBSD).The results showed that the austenite amount was controlled by the 2-phase region heating temperature and the composition and morphology of transformation products were mostly depended on the carbon content in austenite. With the quenching temperature in 2-phase region increasing, the dislocation density in bainite decrease as a result of the block bainite coarsening and mergering, which makes the subgrains with much more low angle grain boundaries (2°~15°) decreasing and the massive ferrite with more high angle grain boundaries increasing gradually. Furthermore, the lath martensite or bainite with high angle grain boundaries and subgrains with low angle grain boundaries gradually increase owing to new austenite grain increasing and growing up. With the roles of above two interactions, some EBSD characteristics such as the packet size and the number fraction of high angle grain boundaries all have a peak present at 740°C

Microband-To-Microshear Band Transition near Grain Boundaries in BCC Steel

2007 ◽  
Vol 558-559 ◽  
pp. 873-878 ◽  
Author(s):  
Dorothée Dorner ◽  
Yoshitaka Adachi ◽  
Kaneaki Tsuzaki
Keyword(s):  
Grain Boundary ◽  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Early Stage ◽  
Compression Tests ◽  
Grain Boundary Characteristics ◽  
Band Transition ◽  
Boundary Characteristics ◽  
Backscatter Diffraction ◽  
Initial Crystal

Compression tests were performed on Fe-3%Si specimens with few grains. The deformation microstructure and microtexture were investigated by electron backscatter diffraction (EBSD) and related to the initial crystal orientation and grain boundary characteristics. Groups of microbands were found that are characterised by a periodic change in crystal orientation, shear at the grain boundary, and the formation of new grains. It is supposed that these microband groups represent an early stage of microshear band development.

Effect of Grain Boundary Characteristics on Lattice Orientations

2007 ◽  
Vol 26-28 ◽  
pp. 1003-1006 ◽  
Author(s):  
Jae Hyung Cho
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Three Dimensional ◽  
Microstructural Characterization ◽  
Grain Boundary Character Distribution ◽  
Average Scheme ◽  
Plane Normal ◽  
Grain Boundary Characteristics ◽  
Correlation Parameters ◽  
Boundary Characteristics

Grain boundary characteristics are defined by five parameter, grain boundary plane normal and misorientation angle/axis between two adjacent grains. The influence of the grain boundary character distribution on lattice evolution during deformation was investigated using three-dimensional crystal plasticity finite element method (CPFEM). Various combinations of grain boundaries were modeled systematically. In analyzing the numerical microstructural characterization obtained by the simulation, orientation average scheme and correlation parameters between misorientation and its special distribution are used. Inter- and intra-grain structures were investigated using the spatial distribution of lattice orientation. Main emphasis was placed on misorientation distributions around grain boundaries, where grain interaction mainly occurred.

Grain Boundary Characteristics Evaluation by Atomistic Investigation Methods

2009 ◽  
Vol 1215 ◽  
Author(s):  
Yoshiyuki Kaji ◽  
Tomohito Tsuru ◽  
Yoji Shibutani
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Density Functional ◽  
Coincidence Site Lattice ◽  
Individual Characteristics ◽  
Material Strength ◽  
Investigation Methods ◽  
Grain Boundary Characteristics ◽  
The Individual ◽  
Boundary Characteristics

AbstractThe grain boundary has been recognized for one of the major defect structures in determining the material strength. It is increasingly important to understand the individual characteristics of various types of grain boundaries due to the recent advances in material miniaturization technique.In the present study three types of grain boundaries of coincidence site lattice (CSL), small angle (SA), and random types are considered as the representative example of grain boundaries. The grain boundary energies and atomic configurations of CSL are first evaluated by first-principle density functional theory (DFT) and the embedded atom method (EAM) calculations. SA and random grain boundaries are subsequently constructed by the same EAM and the fundamental characteristics are investigated by the discrete dislocation mechanics models and the Voronoi polyhedral computational geometric method. As the result, it is found that the local structures are well accorded with the previously reported high resolution-transmission electron microscope (HR-TEM) observations, and that stress distributions of CSL and SA grain boundaries are localized around the grain boundary core. The random grain boundary shows extremely heterogeneous core structures including a lot of pentagon-shaped Voronoi polyhedral resulting from the amorphous-like structure.

scholarly journals Effects of Unidirection/Bidirection Torsional Thermomechanical Processes on Grain Boundary Characteristics and Plasticity of Pure Nickel

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 236
Author(s):  
Yao Lin ◽  
Shan Liu ◽  
Tao Wu ◽  
Guangchun Wang
Keyword(s):  
Grain Boundary ◽  
Electron Backscatter Diffraction ◽  
Pure Nickel ◽  
Random Boundary ◽  
Special Boundaries ◽  
Grain Boundary Characteristics ◽  
Thermomechanical Processes ◽  
Boundary Characteristics ◽  
Boundary Modification ◽  
Boundary Characteristic

The “torsion and annealing” grain boundary modification of pure nickel wires with different diameters was carried out in this paper. The effects of torsional cycles as well as unidirectional/bidirectional torsion methods on grain boundary characteristic distribution and plasticity were investigated. The fraction of special boundaries, grain boundary characteristic distributions and grain orientations of samples with different torsion parameters were detected by electron backscatter diffraction. Hardness measurement was conducted to characterize the plasticity. Then, the relationship between micro grain boundary characteristics and macro plasticity was explored. It was found that the special boundaries, especially Σ3 boundaries, are increased after torsion and annealing and effectively broke the random boundary network. The bidirectional torsion with small torsional circulation unit was the most conducive way to improve the fraction of special boundaries. The experiments also showed that there was a good linear correlation between the fraction of special boundaries and hardness. The plasticization mechanism was that plenty of grains with Σ3 boundaries, [001] orientations and small Taylor factor were generated in the thermomechanical processes. Meanwhile, the special boundaries broke the random boundary network. Therefore, the material was able to achieve greater plastic deformation. Moreover, the mechanism of torsion and annealing on the plasticity of pure nickel was illustrated, which provides theoretical guidance for the pre-plasticization of nickel workpieces.

Combined EBSD and AFM Study of the Corrosion Behaviour of ETP-Cu

2011 ◽  
Vol 702-703 ◽  
pp. 673-676 ◽  
Author(s):  
Linsey Lapeire ◽  
Esther Martinez Lombardia ◽  
Kim Verbeken ◽  
Iris de Graeve ◽  
Leo Kestens ◽  
...  
Keyword(s):  
Recent Literature ◽  
Electron Backscatter Diffraction ◽  
Chemical Interaction ◽  
Corrosion Behaviour ◽  
Corrosion Process ◽  
Crucial Importance ◽  
Atomic Force ◽  
Grain Boundary Characteristics ◽  
Boundary Characteristics ◽  
Backscatter Diffraction

In order to increase the sustainability of metals, a more detailed understanding of the corrosion process is of crucial importance. Current literature often considers corrosion as a purely chemical interaction with a nearly exclusive dependence on compositional effects, while ignoring microstructural and crystallographic properties of the metal surface. Some recent literature data, however, suggest an important effect of microstructural elements such as grain size, crystallographic orientation and grain boundary characteristics. The aim of this work is to obtain a better understanding of the relation between the corrosion behaviour of a metal and its microstructural and crystallographic features. Therefore, warm rolled Electrolytic Tough Pitch (ETP-) Cu was immersed in a 0.1 M NaCl and 0.5M Na2SO4 solution and the combination of Atomic Force Microscope (AFM) and Electron Backscatter Diffraction (EBSD) allowed to identify differences in attack for different crystallographic orientations.

Grain-Boundary Characteristics in Austenitic Steel

1996 ◽  
Vol 54 ◽  
pp. 344-345
Author(s):  
M.D. Caul ◽  
V. Randle
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Austenitic Steel ◽  
Material Properties ◽  
Degrees Of Freedom ◽  
Precipitate Formation ◽  
Grain Boundary Characteristics ◽  
Boundary Geometry ◽  
Individual Grains ◽  
Boundary Characteristics

Grain boundaries are an active area of research interest due to their effect on material property and structure relationships. In order to discuss material properties with regard to grain boundaries it is necessary to know the boundary type. The optimum technique for performing this task is Electron Backscatter Diflfraction (EBSD) in concert with the Scanning Electron Microscope (SEM). By collecting texture measurements in the form of individual orientations from grains it is possible to obtain misorientation measurements from grain boundaries. These measurements are three of the five degrees of freedom necessary to geometrically describe a grain boundary. The other two can be obtained by a serial sectioning technique.Grain boundaries in austenitic steel specimens, isothermally aged at either 700°C or 800°C, have been evaluated with the aim of relating boundary geometry to Cr2N precipitate formation. Samples were analysed using SEM and EBSD in order to obtain orientation measurements of individual grains to misorientations at grain boundaries and to Cr2N precipitates. These precipitates are detrimental to room temperature properties of high nitrogen stainless steels, so a reduction in their formation at grain boundaries would be advantageous. The steel is therefore an ideal candidate material for relating boundaries to material properties. The 700°C isothermally aged sample induces precipitate formation at grain boundaries whereas precipitation by cellular decomposition of austenite occurs in the 800 CC sample. The 700°C sample was used to categorise boundary types using the CSL model and relate this to Cr2N formation. The 800°C sample was used to examine the effect of aging temperature on boundary inclination. Therefore all five degrees of freedom in grain boundary geometry were obtained.

Grain Boundary Characteristics and Stress-induced Damage Morphologies in Sputtered and Electroplated Copper Films

2003 ◽  
Vol 766 ◽  
Author(s):  
Hyun Park ◽  
Soo-Jung Hwang ◽  
Kyu Hwan Oh ◽  
Young-Chang Joo
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Morphological Difference ◽  
High Energy ◽  
Triple Junctions ◽  
Boundary Area ◽  
Boundary Triple ◽  
Surface Damages ◽  
Grain Boundary Characteristics ◽  
Boundary Characteristics

AbstractVarious Cu films were fabricated using sputtering and electroplating with and without additive, and their surface damages after annealing were investigated. After annealing at 435°C, the difference between damage morphologies of the films was observed. In some films stressinduced grooves along the grain boundaries were observed, while in the others voids at the grain boundary triple junctions were observed. It was also observed that the stress-induced groove was formed along the high energy grain boundaries. To explain the morphological difference of surface damages, a simple parameter considering the contributions of grain structures and grain boundary characteristics to surface and grain boundary diffusions is suggested. The effective grain boundary area, which is a function of grain size, film thickness and the fraction of high energy grain boundaries, played a key role in the morphological difference.

Mechanism of Grain Refinement in Aluminium in the Process of Hydrostatic Extrusion

2006 ◽  
Vol 114 ◽  
pp. 109-116 ◽  
Author(s):  
Małgorzata Lewandowska
Keyword(s):  
True Strain ◽  
Strain Range ◽  
Hydrostatic Extrusion ◽  
Pure Aluminium ◽  
High Angle ◽  
Mean Grain Size ◽  
First Pass ◽  
Grain Boundary Characteristics ◽  
The Mean ◽  
Boundary Characteristics

Technically pure aluminium was subjected to three passes by the process of hydrostatic extrusion (HE) to a true strain of 3.8. TEM observations of the microstructure revealed that the first pass of the process refined the grains to 0.6 μm, but the mean grain size remains unaffected by further strain. The microstructural evolution over the strain range from 1 to 4 proceeds through the recovery of grain interiors. Significant changes have been found in grain boundary characteristics. The fraction of high angle grain boundaries profoundly increases as the true strain increases. Various mechanisms for their formation and their relevance to HE are discussed

Defect-Solute Interactions Near Irradiated Grain Boundaries

1993 ◽  
Vol 319 ◽  
Author(s):  
E. P. Simonen ◽  
J. S. Vetrano ◽  
H. L. Heinisch ◽  
S. M. Bruemmer
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Austenitic Stainless Steels ◽  
Back Diffusion ◽  
Metallic Materials ◽  
Grain Boundary Characteristics ◽  
Radiation Induced ◽  
Composition Profiles ◽  
Solute Interactions ◽  
Boundary Characteristics

AbstractDefect-solute interactions control radiation-induced segregation (RIS) to interfacial sinks, such as grain boundaries, in metallic materials. The best studied system in this regard has been austenitic stainless steels. Measurements of grain boundary composition indicate that RIS of major alloying elements is in reasonable agreement with inverse-Kirkendall predictions. The steep and narrow composition profiles are shown to result from limited back diffusion near the boundary. Subsequently, defect-solute interactions that affect the near-boundary defect concentrations strongly affect RIS. The variability in measured RIS may in part be caused by grain boundary characteristics.

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