scholarly journals Lath Martensite Microstructure Modeling: A High-Resolution Crystal Plasticity Simulation Study

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 691
Author(s):  
Francisco-José Gallardo-Basile ◽  
Yannick Naunheim ◽  
Franz Roters ◽  
Martin Diehl
Keyword(s):  
High Resolution ◽  
Mechanical Behavior ◽  
Crystal Plasticity ◽  
Lath Martensite ◽  
Three Dimensional ◽  
Building Blocks ◽  
Quantitative Agreement ◽  
Carbon Steels ◽  
Plastic Behavior ◽  
Austenitic Phase

Lath martensite is a complex hierarchical compound structure that forms during rapid cooling of carbon steels from the austenitic phase. At the smallest, i.e., ‘single crystal’ scale, individual, elongated domains, form the elemental microstructural building blocks: the name-giving laths. Several laths of nearly identical crystallographic orientation are grouped together to blocks, in which–depending on the exact material characteristics–clearly distinguishable subblocks might be observed. Several blocks with the same habit plane together form a packet of which typically three to four together finally make up the former parent austenitic grain. Here, a fully parametrized approach is presented which converts an austenitic polycrystal representation into martensitic microstructures incorporating all these details. Two-dimensional (2D) and three-dimensional (3D) Representative Volume Elements (RVEs) are generated based on prior austenite microstructure reconstructed from a 2D experimental martensitic microstructure. The RVEs are used for high-resolution crystal plasticity simulations with a fast spectral method-based solver and a phenomenological constitutive description. The comparison of the results obtained from the 2D experimental microstructure and the 2D RVEs reveals a high quantitative agreement. The stress and strain distributions and their characteristics change significantly if 3D microstructures are used. Further simulations are conducted to systematically investigate the influence of microstructural parameters, such as lath aspect ratio, lath volume, subblock thickness, orientation scatter, and prior austenitic grain shape on the global and local mechanical behavior. These microstructural features happen to change the local mechanical behavior, whereas the average stress–strain response is not significantly altered. Correlations between the microstructure and the plastic behavior are established.

Crystal Plasticity Finite Element Analysis Based on Crystal Orientation Mapping with Three-Dimensional X-Ray Diffraction Microscopy

2014 ◽  
Vol 777 ◽  
pp. 142-147 ◽  
Author(s):  
Daigo Setoyama ◽  
Yujiro Hayashi ◽  
Noritoshi Iwata
Keyword(s):  
Finite Element ◽  
Crystal Plasticity ◽  
Crystal Orientation ◽  
Three Dimensional ◽  
Deformation Analysis ◽  
Plastic Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Plasticity Finite Element ◽  
Deformation State

In other study we examined the plastic behavior for polycrystalline iron by three-dimensional x-ray diffraction (3DXRD) experiment. In this study we analyze the behavior by crystal plasticity finite element (CPFE) analysis, to confirm the validity of application to the deformation analysis of engineering steels of a couple of constitutive models. In the CPFE analysis, the observed microstructure and its crystal orientation are modeled with finite elements to take the inter-granular and intra-granular interactions into consideration. The plastic deformation state of the finite element model was computed by means of CPFE analysis based on the {110}<111> slip system in body centered cubic (BCC) crystal. The experiment showed that the most of the grains rotated toward the preferred orientation <110> along the tensile axis and that intra-granular orientation spread and multi-directionally rotated as the tensile strain increased. These results are reproduced by the CPFE analysis, in which the influence of interaction between neighboring grains is taken into consideration.

Three-Dimensional analysis of oxide-oxide directionally solidified eutectic interfaces by high-resolution Microscopy and Electron Energy Loss Spectroscopy

1995 ◽  
Vol 53 ◽  
pp. 328-329
Author(s):  
E.C. Dickey ◽  
V.P. Dravid ◽  
A. Revcolevschi
Keyword(s):  
High Resolution ◽  
Mechanical Behavior ◽  
Bulk Material ◽  
Three Dimensional ◽  
High Resolution Electron Microscopy ◽  
Ceramic Composites ◽  
Three Dimensions ◽  
Structure Property ◽  
Directionally Solidified ◽  
Orientation Relationships

It is well appreciated that the strength of heterophase interfaces in ceramic composites plays an extremely influential role in the macroscopic mechanical behavior of the bulk material. It is therefore useful to understand the structure of such interfaces in order to make structure/ property relationships between interface structure and mechanical behavior. High Resolution Electron Microscopy (HREM) is an extremely useful technique for elucidating the atomic structure of heterophase interfaces in ceramic materials, but HREM has typically been used to image lattice planes along only one zone axis. Often, however, it is useful to obtain three-dimensional information about the interface in order to fully appreciate and understand the complete relaxation and structure of the interface. Directionally solidified eutectics (DSEs) offer a unique opportunity to study heterophase interfaces in three dimensions, because they contain numerous, identical interfaces with consistent crystallographic orientation relationships between the two phases. Of particular interest are those eutectics that have lamellar morphologies, because the planar interfaces may be viewed along two orthogonal directions (Fig.l).

scholarly journals Method for Attaining Dimensionally Accurate Conditions for High-Resolution Three-Dimensional Printing Ceramic Composite Structures Using MicroCLIP Process

2019 ◽  
Vol 7 (3) ◽  
Author(s):  
Henry Oliver T. Ware ◽  
Cheng Sun
Keyword(s):  
High Resolution ◽  
Composite Structures ◽  
Uv Light ◽  
Incident Light ◽  
Three Dimensional ◽  
Building Blocks ◽  
Ceramic Particles ◽  
Traditional Manufacturing ◽  
Continuous Fabrication ◽  
Exposure Conditions

Continuous liquid interface production (CLIP) utilizes projection ultraviolet (UV) light and oxygen inhibition to transform the sequential layered three-dimensional (3D) manufacturing into a continuous fabrication flow with tremendous improved fabrication speed and structure integrity. Incorporating ceramic particles to the photo-curable polymers allows for additive manufacturing of ceramic parts featuring sophisticated geometries, mitigating the difficulties associated with traditional manufacturing processes. The presence of ceramic particles within the ink, however, strongly scatters the incident UV light. In the high-resolution CLIP (microCLIP) process, the scattering effect can significantly alter the process characteristics, resulting in broadening of lateral feature dimensions alongside curing depth reduction. Varying exposure conditions to accommodate scattering additionally affects the oxygen deadzone thickness (DZ), which is dependent on power of incident light. This introduces a systematic defocusing error for large deadzone thickness to further complicate process control, such as the unwanted narrowing of part features. In this work, we developed a systematic framework for process optimization by balancing those effects via experimental characterization. We showed that the reported method can provide a set of optimal process parameters (UV power and stage speed) for high-resolution 3D fabrication in accommodating the distinct characteristics of given photo-curable ceramic ink. The method to optimize process parameter was validated experimentally via fabricating a gradient index Luneburg lens comprising densely packed woodpile building-blocks with a strut width of 100 μm and a layer thickness of 60 μm using microCLIP at dimensionally accurate exposure conditions.

High Resolution Microscopy of Multi-Layered Biological Crystals

1982 ◽  
Vol 40 ◽  
pp. 80-83
Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Two Dimensional ◽  
Biological Objects ◽  
Density Maps ◽  
Density Map ◽  
Complex Crystal ◽  
High Resolution Microscopy

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.

Electron crystallographic determination of the 3-D structure of staurolite at atomic resolution

1991 ◽  
Vol 49 ◽  
pp. 540-541
Author(s):  
Kenneth H. Downing ◽  
Hu Meisheng ◽  
Hans-Rudolf Went ◽  
Michael A. O'Keefe
Keyword(s):  
High Resolution ◽  
Three Dimensional ◽  
High Resolution Electron Microscopy ◽  
Atomic Resolution ◽  
Dimensional Structure ◽  
Structure Information ◽  
Resolution Electron ◽  
Scattering Effects ◽  
High Resolution Images ◽  
Effects Of Radiation

With current advances in electron microscope design, high resolution electron microscopy has become routine, and point resolutions of better than 2Å have been obtained in images of many inorganic crystals. Although this resolution is sufficient to resolve interatomic spacings, interpretation generally requires comparison of experimental images with calculations. Since the images are two-dimensional representations of projections of the full three-dimensional structure, information is invariably lost in the overlapping images of atoms at various heights. The technique of electron crystallography, in which information from several views of a crystal is combined, has been developed to obtain three-dimensional information on proteins. The resolution in images of proteins is severely limited by effects of radiation damage. In principle, atomic-resolution, 3D reconstructions should be obtainable from specimens that are resistant to damage. The most serious problem would appear to be in obtaining high-resolution images from areas that are thin enough that dynamical scattering effects can be ignored.

Three-Dimensional Immunoelectron Microscopy of Yeast Cells by a New High-Resolution Replica Method

1985 ◽  
Vol 43 ◽  
pp. 562-563
Author(s):  
Hirano T. ◽  
M. Yamaguchi ◽  
M. Hayashi ◽  
Y. Sekiguchi ◽  
A. Tanaka
Keyword(s):  
High Resolution ◽  
Plasma Polymerization ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Replica Method ◽  
Yeast Cells ◽  
Dynamic Aspect ◽  
Replica Technique ◽  
Gaseous Hydrocarbon ◽  
Transmission Electron

A plasma polymerization film replica method is a new high resolution replica technique devised by Tanaka et al. in 1978. It has been developed for investigation of the three dimensional ultrastructure in biological or nonbiological specimens with the transmission electron microscope. This method is based on direct observation of the single-stage replica film, which was obtained by directly coating on the specimen surface. A plasma polymerization film was deposited by gaseous hydrocarbon monomer in a glow discharge.The present study further developed the freeze fracture method by means of a plasma polymerization film produces a three dimensional replica of chemically untreated cells and provides a clear evidence of fine structure of the yeast plasma membrane, especially the dynamic aspect of the structure of invagination (Figure 1).

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