scholarly journals A New Experimental Method for Determining the Thickness of Thin Surface Layers of Intensive Plastic Deformation Using Electron Backscatter Diffraction Data

Symmetry ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 677
Author(s):  
Alexander Smirnov ◽  
Evgeniya Smirnova ◽  
Sergey Alexandrov
Keyword(s):  
Plastic Deformation ◽  
Electron Backscatter Diffraction ◽  
Thin Layers ◽  
New Method ◽  
Metallic Materials ◽  
Surface Layers ◽  
Kernel Average Misorientation ◽  
Electron Backscatter ◽  
Properties Of Materials ◽  
Backscatter Diffraction

It is, in general, essential to investigate correlations between the microstructure and properties of materials. Plastic deformation often localizes within thin layers. As a result, many material properties within such layers are very different from the properties in bulk. The present paper proposes a new method for determining the thickness of a thin surface layer of intensive plastic deformation in metallic materials. For various types of materials, such layers are often generated near frictional interfaces. The method is based on data obtained by Electron Backscatter Diffraction. The results obtained are compared with those obtained by an alternative method based on microhardness measurements. The new method allows for determining the layer thickness of several microns in specimens after grinding. In contrast, the measurement of microhardness does not reveal the presence of this layer. The grain-based and kernel-based types of algorithms are also adopted for determining the thickness of the layer. Data processed by the strain contouring and kernel average misorientation algorithms are given to illustrate this method. It is shown that these algorithms do not clearly detect the boundary between the layer of intensive plastic deformation and the bulk. As a result, these algorithms are unable to determine the thickness of the layer with high accuracy.

Shear Pressing for Grain Refinement of Al-Mg-Li Sheet

2007 ◽  
Vol 546-549 ◽  
pp. 885-888
Author(s):  
Yu Xuan Du ◽  
Xin Ming Zhang ◽  
Ling Ying Ye ◽  
Zhi Hui Luo
Keyword(s):  
Shear Deformation ◽  
Grain Refinement ◽  
Electron Backscatter Diffraction ◽  
Grain Structure ◽  
Grain Refining ◽  
Metallic Materials ◽  
Inclined Plane ◽  
Fine Grained ◽  
Electron Backscatter ◽  
Backscatter Diffraction

A novel shear-deformation technique, named ‘shear pressing’ (SP), was developed for fabrication of plate-shaped fine grained metallic materials. The principle of SP is that a material is subjected to shear deformation by utilizing pressing with inclined plane dies. A micrometer order grain structure was obtained in an Al-Mg-Li alloy at strain of ε = -2.3 by utilizing this technique. The grain refinement sequences during pressing were examined by electron backscatter diffraction. The enhancement of grain refinement to the Al-Mg-Li alloy was compared with plane strain compression (PSC) at similar strains. The effect of the shear strain on the accelerated grain refining during compressing has been discussed.

Denoising of crystal orientation maps

2019 ◽  
Vol 52 (5) ◽  
pp. 984-996 ◽  
Author(s):  
R. Hielscher ◽  
C. B. Silbermann ◽  
E. Schmidl ◽  
Joern Ihlemann
Keyword(s):  
Variational Methods ◽  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Sliding Window ◽  
Orientation Data ◽  
Kernel Average Misorientation ◽  
Orientation Maps ◽  
Electron Backscatter ◽  
Backscatter Diffraction

This paper compares several well known sliding-window methods for denoising crystal orientation data with variational methods adapted from mathematical image analysis. The variational methods turn out to be much more powerful in terms of preserving low-angle grain boundaries and filling holes of non-indexed orientations. The effect of denoising on the determination of the kernel average misorientation and the geometrically necessary dislocation density is also discussed. Synthetic as well as experimental data are considered for this comparison. The examples demonstrate that variational denoising techniques are capable of significantly improving the accuracy of properties derived from electron backscatter diffraction maps.

scholarly journals Understanding the Machinability of Austempered Ductile Iron (ADI)

2018 ◽  
Vol 925 ◽  
pp. 311-317 ◽  
Author(s):  
Dika Handayani ◽  
Robert C. Voigt ◽  
Kathy Hayrynen
Keyword(s):  
Plastic Deformation ◽  
Martensitic Transformation ◽  
Severe Plastic Deformation ◽  
Ductile Iron ◽  
Cutting Tool ◽  
Electron Backscatter Diffraction ◽  
Austempered Ductile Iron ◽  
Finish Machining ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Guidelines for production milling, turning and drilling of the standard grades of austempered ductile irons (ADI) have been established. Electron Backscatter Diffraction (EBSD) characterization has clearly shown that severe plastic deformation in the machining-affected-zone, ahead of and beneath the cutting tool, will cause strain-induced martensitic transformation of the austenite in the ausferrite structure that inhibits machinability. This phenomenon is particularly of concern during finish machining where small depths of cut are strongly influenced by surface martensite from prior machining passes.

Observations of Dislocation Structure in AA 7050 by EBSD

2011 ◽  
Vol 702-703 ◽  
pp. 493-498 ◽  
Author(s):  
C.C. Merriman ◽  
David P. Field
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Dislocation Density ◽  
Cell Walls ◽  
Electron Backscatter Diffraction ◽  
Geometrically Necessary Dislocation ◽  
Dislocation Densities ◽  
Electron Backscatter ◽  
Dislocation Density Tensor ◽  
Backscatter Diffraction

During and after plastic deformation of metals, dislocations tend to evolve into generally well-defined structures that may include tangles, bands, cell walls, and various additional features. Observation of these structures by electron backscatter diffraction is only accomplished by analysis of changes in orientation from one position to the next. Excess (or geometrically necessary) dislocation densities can be inferred from 2D measurements or obtained directly from 3D measurements as indicated by Nye’s dislocation density tensor. Evolution of excess dislocation densities was measured for a split channel die specimen of aluminum alloy 7050 in the T7451 temper. Densities evolved by a factor or 1.6 for compressive deformations of 15%.

A new method for locating Kikuchi bands in electron backscatter diffraction patterns

2019 ◽  
Vol 82 (12) ◽  
pp. 2035-2041
Author(s):  
Yongsheng Zhang ◽  
Shangqiang Fang ◽  
Chucheng Lin ◽  
Jimei Zhang ◽  
Caifen Jiang ◽  
...  
Keyword(s):  
Electron Backscatter Diffraction ◽  
New Method ◽  
Electron Backscatter ◽  
Diffraction Patterns ◽  
Backscatter Diffraction

scholarly journals An Examination of the Composition and Microstructure of Coarse Intermetallic Particles in AA2099-T8, Including Li Detection

2018 ◽  
Vol 24 (4) ◽  
pp. 325-341 ◽  
Author(s):  
Colin M. MacRae ◽  
Anthony E. Hughes ◽  
James S. Laird ◽  
A. M. Glenn ◽  
Nicholas C. Wilson ◽  
...  
Keyword(s):  
Electron Probe ◽  
Electron Backscatter Diffraction ◽  
Ebsd Analysis ◽  
Stored Energy ◽  
Kernel Average Misorientation ◽  
X Ray ◽  
Energy Proton ◽  
Intermetallic Particles ◽  
Electron Backscatter ◽  
Backscatter Diffraction

AbstractElectron and proton microprobes, along with electron backscatter diffraction (EBSD) analysis were used to study the microstructure of the contemporary Al–Cu–Li alloy AA2099-T8. In electron probe microanalysis, wavelength and energy dispersive X-ray spectrometry were used in parallel with soft X-ray emission spectroscopy (SXES) to characterize the microstructure of AA2099-T8. The electron microprobe was able to identify five unique compositions for constituent intermetallic (IM) particles containing combinations of Al, Cu, Fe, Mn, and Zn. A sixth IM type was found to be rich in Ti and B (suggesting TiB2), and a seventh IM type contained Si. EBSD patterns for the five constituent IM particles containing Al, Cu, Fe, Mn, and Zn indicated that they were isomorphous with four phases in the 2xxx series aluminium alloys including Al6(Fe, Mn), Al13(Fe, Mn)4 (two slightly different compositions), Al37Cu2Fe12 and Al7Cu2Fe. SXES revealed that Li was present in some constituent IM particles. Al SXES mapping revealed an Al-enriched (i.e., Cu, Li-depleted) zone in the grain boundary network. From the EBSD analysis, the kernel average misorientation map showed higher levels of localized misorientation in this region, suggesting greater deformation or stored energy. Proton-induced X-ray emission revealed banding of the TiB2 IM particles and Cu inter-band enrichment.

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