scholarly journals An Accurate Method for Crystallographic Reconstruction of Parent Austenite from Inherited Martensite in a Low-Alloy Steel

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 358 ◽  
Author(s):  
Daokuan Wang ◽  
Junsong Jin ◽  
Qiaomin Li ◽  
Xinyun Wang
Keyword(s):  
Electron Backscatter Diffraction ◽  
Accurate Method ◽  
Reconstruction Method ◽  
Low Alloy Steels ◽  
Low Alloy Steel ◽  
Reconstruction Procedure ◽  
Electron Backscatter ◽  
Alloy Steels ◽  
Backscatter Diffraction ◽  
Parent Austenite

The microstructure of austenite at high temperatures, which cannot be reserved at room temperatures, determines the properties of its transformed phase in low-alloy steels. Consequently, an accurate method is herein developed to reconstruct local orientations of the parent austenite ( γ ) phase from electron backscatter diffraction maps of the martensite ( α ′ ) microstructure. The orientation map of α ′ is cropped into a grid of data squares as the reconstruction unit. The cropped square is then divided into the square inherited from only one γ grain and the square inherited from more than one γ grain. The local orientations around parent γ grain boundaries are more accurately determined using a newly proposed reconstruction criterion. Furthermore, the solution spaces for the orientation relationship and the parent γ orientation are refined, which simultaneously improves the calculation accuracy and efficiency of reconstruction procedure. The validated reconstruction method is applied to obtain local orientations of the deformed γ microstructure accurately.

Analysis of Recrystallization Behavior of Hot-Deformed Austenite Reconstructed from EBSD Orientation Maps of Lath Martensite

2016 ◽  
Vol 879 ◽  
pp. 2389-2394
Author(s):  
Manabu Kubota ◽  
Kohsaku Ushioda ◽  
Goro Miyamoto ◽  
Tadashi Furuhara
Keyword(s):  
Hot Deformation ◽  
Lath Martensite ◽  
New Method ◽  
Reconstruction Method ◽  
Low Alloy Steels ◽  
Recrystallization Behavior ◽  
Compression Direction ◽  
Orientation Map ◽  
Alloy Steels ◽  
Parent Austenite

The recrystallization behavior of hot-deformed austenite of 0.55% C low alloy steels at 900, 850 and 800°C was investigated by a conventional double-hit compression test and a new method which reconstructs the parent austenite orientation map from an EBSD (electron backscattering diffraction) orientation map of daughter lath martensite. The new method can clearly reconstruct the parent austenite structure at high temperature from the daughter lath martensite structure and we can obtain the information on crystal orientation of the work-hardened austenite. It was revealed that recrystallization of austenite at 800 °C is significantly retarded by the addition of 0.1% V. The strong texture of <110> parallel to the compression direction develops just after the hot-deformation, but this texture becomes weaker as the recrystallization progresses. By applying the reconstruction method, it becomes possible to evaluate various phenomena related to the hot-deformation of austenite

The Geometric Compatibility Factor Determining Brittle Crack Propagation Across Boundary in Bainitic Low Alloy Steels

2001 ◽  
Vol 7 (S2) ◽  
pp. 1266-1267
Author(s):  
Yong-Jun Oh ◽  
Min-Chul Kim ◽  
Jun-Hwa Hong
Keyword(s):  
Crack Propagation ◽  
Electron Backscatter Diffraction ◽  
Low Alloy Steels ◽  
Brittle Crack ◽  
Compatibility Factor ◽  
Boundary Properties ◽  
Alloy Steels ◽  
Properties Of Materials ◽  
Backscatter Diffraction ◽  
Geometric Compatibility

Boundary properties between two adjacent grains with different crystallographic orientation relation are important factors in deciding the mechanical properties of materials. in our previous reports, we introduced the geometric compatibility equation as a factor determining the brittle crack propagation condition into the adjacent grain in banitic low alloy steel as follows:M = cos α · cos θwhere α is the angle between crack normal in the cracked grain-I and normal to (001) plane in the adjacent grain-II and θ is the angle between normal to (001) plane in the grain II and loading axis.(see FIG. 1) Higher M gives greater possibility to the crack propagation. The geometric compatibility factor (M) could be easily calculated from the crystallographic data obtained from Electron Backscatter Diffraction (EBSD) analysis, and successfully predicted actual crack propagation plane. We also found that there was a critical M value to arrest the brittle crack propagation at the boundaries.

Effects of Transformation Temperature on Variant Grouping of Bainitic Ferrite in Low Carbon Steel

2011 ◽  
Vol 172-174 ◽  
pp. 155-160
Author(s):  
Naoki Takayama ◽  
Goro Miyamoto ◽  
Tadashi Furuhara
Keyword(s):  
Transformation Temperature ◽  
Electron Backscatter Diffraction ◽  
Lath Martensite ◽  
Bainitic Ferrite ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Low Alloy Steel ◽  
Bainite Structure ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Effects of transformation temperature on variant grouping tendency of bainitic ferrite in a low carbon low alloy steel transformed isothermally are investigated by means of electron backscatter diffraction analysis. Baintic variants of Kurdjumov-Sachs (K-S) orientation relationship belonging to the same Bain correspondence tend to form adjacently in the bainite structure formed at 823K, while the K-S variants sharing the same close-packed plane parallel relation form adjacently in the bainite structure formed at 723K and lath martensite formed by quenching.

Analysis of variant selection in friction-stir-processed high-strength low-alloy steels

2013 ◽  
Vol 46 (3) ◽  
pp. 716-725 ◽  
Author(s):  
Majid Abbasi ◽  
Tracy W. Nelson ◽  
Carl D. Sorensen
Keyword(s):  
Electron Backscatter Diffraction ◽  
High Strength ◽  
Low Alloy Steels ◽  
Variant Selection ◽  
Dimensional Approach ◽  
Friction Stir ◽  
Interfacial Energies ◽  
Austenite Grain ◽  
Alloy Steels ◽  
Backscatter Diffraction

Variant selection in friction-stir-welded high-strength low-alloy steels has been studied using the electron backscatter diffraction and prior austenite (PA) reconstruction techniques described in previous papers. A hypothesis for variant selection has been proposed based on grain-boundary interfacial energy and misorientation. This study focuses on austenite 〈111〉 boundaries with a two-dimensional approach. Results indicate that variant selection is strongly dependent on misorientation. Certain PA misorientations produce combinations of variants that minimize the interfacial energies between a ferrite nucleus and a neighboring austenite grain, and between adjoining ferrite nuclei along the boundary between two PA grains. PA grains that exhibit a 60° 〈111〉 misorientation between them satisfy both these conditions for a combination of variants. These PA boundaries exhibit strong variant selection. As a result, the density of these boundary types influences the overall variant selection. Additionally, variant selection is more prevalent in small PA grains (<150 µm), which is probably a result of limited intragranular nucleation. Nearly all variants are present in larger PA grains.

Cross Section Analysis of Cu Filled TSVs Based on High Throughput Plasma-FIB Milling

2012 ◽  
Author(s):  
Frank Altmann ◽  
Jens Beyersdorfer ◽  
Jan Schischka ◽  
Michael Krause ◽  
German Franz ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Section ◽  
High Throughput ◽  
Cross Sections ◽  
Electron Backscatter Diffraction ◽  
Grain Structure ◽  
Electron Backscatter ◽  
Section Surface ◽  
Backscatter Diffraction ◽  
Section Analysis

Abstract In this paper the new Vion™ Plasma-FIB system, developed by FEI, is evaluated for cross sectioning of Cu filled Through Silicon Via (TSV) interconnects. The aim of the study presented in this paper is to evaluate and optimise different Plasma-FIB (P-FIB) milling strategies in terms of performance and cross section surface quality. The sufficient preservation of microstructures within cross sections is crucial for subsequent Electron Backscatter Diffraction (EBSD) grain structure analyses and a high resolution interface characterisation by TEM.

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