Assessment of Welding-Induced Plasticity in Austenitic Steel Weldments

2016 ◽  
Author(s):  
Ondrej Muránsky ◽  
Cory J. Hamelin ◽  
Minh Tran ◽  
Chedly Braham ◽  
Michael C. Smith
Keyword(s):  
Structural Integrity ◽  
Electron Backscatter Diffraction ◽  
Constitutive Models ◽  
Region Of Interest ◽  
Characterization Methods ◽  
Macro Scale ◽  
Proper Definition ◽  
Aisi 316 ◽  
Definition Of ◽  
Backscatter Diffraction

Historically, weld residual stresses (WRS) have been used as the primary validation parameter for welding simulations, largely due to the importance of predicting WRS for structural integrity assessments. However, the extent of welding-induced plasticity (WIP) caused by the plastic flow of near-weld material is also an important characteristic affecting weld performance. WIP has been shown to negatively affect weld integrity, since the associated accumulation of defects (dislocations) in the material will accelerate the nucleation of macro-scale defects that lead to component failure. Information on WIP is particularly important when attempting to validate the constitutive models used for weld simulation, and can assist with the proper definition of material yield strength. The present study highlights two approaches to assess WIP in welded structures. The first approach involves the development of a micro-hardness correlation to infer the level of WIP across the near-weld region. The second approach uses electron backscatter diffraction (EBSD) data to directly calculate the average crystal misorientation in the region of interest, which is proportional to the amount of geometrically necessary dislocations present. The dissimilar approach to determine WIP between the two characterization methods allows a degree of confidence in the results obtained, therefore providing an accurate dataset for weld model validation. To exemplify this point, the two approaches are used to characterize WIP across a three-pass slot weld in AISI 316 steel (NeT TG4 specimen), and the results are compared to weld modelling predictions.

scholarly journals Validation of three-dimensional diffraction contrast tomography reconstructions by means of electron backscatter diffraction characterization

2013 ◽  
Vol 46 (4) ◽  
pp. 1145-1150 ◽  
Author(s):  
Melanie Syha ◽  
Andreas Trenkle ◽  
Barbara Lödermann ◽  
Andreas Graff ◽  
Wolfgang Ludwig ◽  
...  
Keyword(s):  
Electron Backscatter Diffraction ◽  
Three Dimensional ◽  
Data Reconstruction ◽  
Characterization Methods ◽  
Diffraction Contrast ◽  
Ebsd Data ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Tomography Data ◽  
Good Agreement

Microstructure reconstructions resulting from diffraction contrast tomography data of polycrystalline bulk strontium titanate were reinvestigated by means of electron backscatter diffraction (EBSD) characterization. Corresponding two-dimensional grain maps from the two characterization methods were aligned and compared, focusing on the spatial resolution at the internal interfaces. The compared grain boundary networks show a remarkably good agreement both morphologically and in crystallographic orientation. Deviations are critically assessed and discussed in the context of diffraction data reconstruction and EBSD data collection techniques.

Crystal chemistry of clinker relicts from aged cementitious materials

2014 ◽  
Vol 47 (5) ◽  
pp. 1626-1637 ◽  
Author(s):  
Michele Secco ◽  
Luca Peruzzo ◽  
Laurie Palasse ◽  
Gilberto Artioli ◽  
Alberto Viani ◽  
...  
Keyword(s):  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Chemical Properties ◽  
Cementitious Materials ◽  
Operating Conditions ◽  
General Tendency ◽  
Hydration Kinetics ◽  
Definition Of ◽  
Backscatter Diffraction

Despite the general tendency to consider Portland cement virtually fully hydrated within a few years, the occurrence of non-reacted clinker phases in cementitious materials that are several decades old is rather common. In this work, the integration of microstructural analysis by scanning electron microscopy and quantitative microchemical and micromineralogical characterization techniques, such as electron microprobe analysis and electron backscatter diffraction, allowed the definition of the crystal-chemical properties of partially hydrated cement residuals within different types of aged cementitious materials. The results on several clinker relicts show that the calcium silicate phases are transformed systematically and pervasively by hydration reactions, whereas the aluminate and ferrite phases do frequently persist in the anhydrous state. These relict phases may be distinguished through their peculiar chemical, mineralogical and textural features. These observations raise interesting questions concerning the long-term hydration kinetics of clinker phases and the durability behaviour of cementitious materials in operating conditions.

scholarly journals Characterization Methods for the Effect of Microbial Mineralization on the Microstructure of Hardened C3S Paste

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yanqiang Chen ◽  
Chunxiang Qian ◽  
Hengyi Zhou
Keyword(s):  
Electron Backscatter Diffraction ◽  
Hydration Product ◽  
X Ray Diffraction ◽  
Hydration Degree ◽  
Characterization Methods ◽  
X Ray ◽  
Ft Ir ◽  
Different Depths ◽  
Backscatter Diffraction ◽  
Microbial Mineralization

Microbial mineralization has a significant effect on the hydration process of cement-based materials. This paper mainly studied the characterization methods for hydration degree and hydration product of C3S in hardened paste under microbial mineralization. Quantitative X-ray diffraction (QXRD), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT-IR), and electron backscatter diffraction (EBSD) were used and compared. The results showed that microbial mineralization increased the hydration degree of T-C3S. QXRD and EBSD could be used to characterize the content of C3S, and there were few differences between the two methods. TG could accurately characterize the content of Ca(OH)2 and CaCO3 at different depths of the sample, and FT-IR could qualitatively characterize the presence of Ca(OH)2 and CaCO3.

scholarly journals Automated Twin Identification Technique for Use with Electron Backscatter Diffraction

2005 ◽  
Vol 495-497 ◽  
pp. 191-196 ◽  
Author(s):  
B.L. Henrie ◽  
Thomas A. Mason ◽  
J.F. Bingert
Keyword(s):  
Electron Backscatter Diffraction ◽  
Deformation Twinning ◽  
Complex Nature ◽  
Correct Identification ◽  
Electron Backscatter ◽  
Identification Technique ◽  
Parent Orientation ◽  
Voting Scheme ◽  
Definition Of ◽  
Backscatter Diffraction

Historically, twinning classification has been obtained by optical microscopy, bulk x-ray and neutron diffraction, and transmission electron microscopy (TEM). Recent research has shown that automated electron backscatter diffraction (EBSD) can be used to quantify twin content and thereby greatly improve the reliability of twinning statistics. An automated twin identification technique for use with EBSD has facilitated a greater understanding of deformation twinning in materials. The key features of this automated framework are the use of the crystallographic definition of twin relationships, and the correct identification of the parent orientation in a parent/twin pair. The complex nature of the parent/twin interactions required the use of a voting scheme to correctly identify parent orientations. In those few cases where the voting scheme was unable to determine parent orientation (< 2%) the algorithm allows for manual selection. Twin area fractions are categorized by operative twin systems along with secondary and tertiary twinning. These statistics are reported for deformation and annealing twin populations in deformed a-zirconium and asannealed 316L stainless steel, respectively. These improved twin statistics can help provide insight into the effect of deformation processes on microstructural evolution, as well as provide validation of plasticity models for materials that exhibit deformation twinning.

Application of Electron Backscatter Diffraction to Shape Memory Alloys

2012 ◽  
Vol 521 ◽  
pp. 255-268 ◽  
Author(s):  
Paola Bassani
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Electron Backscatter Diffraction ◽  
Point Of View ◽  
Theoretical Point ◽  
Characterization Methods ◽  
Research Areas ◽  
Time Shape ◽  
Electron Backscatter ◽  
Backscatter Diffraction

This overview highlights very recent application of electron backscatter diffraction (EBSD) to shape memory alloys, as main investigation technique but also as ancillary technique for other characterization methods. Over the last two decades EBSD in the scanning electron microscope has become a powerful tool for the characterization of many materials and transformation. In the mean time, shape memory alloys (SMA) are continuously studied: from a theoretical point of view, in order to clarify unsolved fundamentals of their phase transformations and characterize or develop new SMA systems, and from an engineering point of view, to solve design and processing problems related to the continuously growing examples of applications. Application of EBSD to SMA, even if hindered by limitations generally found also in other metallic system when phase transformation and martensitic phases are involved, provided useful information for both research areas.

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.

Sign in / Sign up

Export Citation Format

Share Document