scholarly journals Recent Advances in EBSD Characterization of Metals

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1097
Author(s):  
Íris Carneiro ◽  
Sónia Simões

Electron backscatter diffraction (EBSD) has been attracting enormous interest in the microstructural characterization of metals in recent years. This characterization technique has several advantages over conventional ones, since it allows obtaining a wide range of characterization possibilities in a single method, which is not possible in others. The grain size, crystallographic orientation, texture, and grain boundary character distribution can be obtained by EBSD analysis. Despite the limited resolution of this technique (20–50 nm), EBSD is powerful, even for nanostructured materials. Through this technique, the microstructure can be characterized at different scales and levels with a high number of microstructural characteristics. It is known that the mechanical properties are strongly related to several microstructural aspects such as the size, shape, and distribution of grains, the presence of texture, grain boundaries character, and also the grain boundary plane distribution. In this context, this work aims to describe and discuss the possibilities of microstructural characterization, recent advances, the challenges in sample preparation, and the application of the EBSD in the characterization of metals.

2007 ◽  
Vol 539-543 ◽  
pp. 3389-3394 ◽  
Author(s):  
Wei Guo Wang

The progress of grain boundary engineering (GBE) is overviewed and the challenges for further investigations emphasized. It points out that, the electron backscatter diffraction (EBSD) reconstruction of grain boundaries, which gives the information of connectivity interruption of general high angle boundaries (HABs), is more significant than purely pursuing high frequency of so-called special boundaries. The criterion for the optimization of grain boundary character distribution (GBCD) needs to be established. The energy spectrum and the degradation susceptibility of grain boundaries of various characters including HABs and low Σ(Σ≤29) coincidence site lattice (CSL) needs to be studied and ascertained. And finally, the newly proposed model of non-coherent Σ3 interactions for GBCD optimization are discussed.


2005 ◽  
Vol 502 ◽  
pp. 151-156
Author(s):  
Yasuyuki Kaneno ◽  
Takayuki Takasugi

Microstructural feature of the recrystallized Co-based (Co3Ti) and Ni-based (Ni3(Si,Ti) and Ni3Fe) ordered alloys with L12 structure was investigated by the electron backscatter diffraction (EBSD) method, with emphasis on grain boundary character distribution (GBCD). For comparison, the GBCDs of the recrystallized Co-Ni, Ni-Fe and 70/30 brass disordered alloys, and also copper, nickel and aluminum pure metals with A1 (fcc) structure, which have widely different stacking fault energies, were also determined. The frequency of Σ3 boundary for the Co-based alloys was higher than that for the Ni-based alloys, regardless of ordered L12 alloy or disordered fcc alloy, indicating that the frequency of Σ3 boundary was primarily dominated by stacking fault energy. Furthermore, the effect of ordering energy on structure and energy of the grain boundaries including Σ3 boundary in the ordered L12 alloys was discussed.


2013 ◽  
Vol 19 (S4) ◽  
pp. 103-104
Author(s):  
C.B. Garcia ◽  
E. Ariza ◽  
C.J. Tavares

Zinc Oxide is a wide band-gap compound semiconductor that has been used in optoelectronic and photovoltaic applications due to its good electrical and optical properties. Aluminium has been an efficient n-type dopant for ZnO to produce low resistivity films and high transparency to visible light. In addition, the improvement of these properties also depends on the morphology, crystalline structure and deposition parameters. In this work, ZnO:Al films were produced by d.c. pulsed magnetron sputtering deposition from a ZnO ceramic target (2.0 wt% Al2O3) on glass substrates, at a temperature of 250 ºC.The crystallographic orientation of aluminum doped zinc oxide (ZnO:Al) thin films has been studied by Electron Backscatter Diffraction (EBSD) technique. EBSD coupled with Scanning Electron Microscopy (SEM) is a powerful tool for the microstructural and crystallographic characterization of a wide range of materials.The investigation by EBSD technique of such films presents some challenges since this analysis requires a flat and smooth surface. This is a necessary condition to avoid any shadow effects during the experiments performed with high tilting conditions (70º). This is also essential to ensure a good control of the three dimensional projection of the crystalline axes on the geometrical references related to the sample.Crystalline texture is described by the inverse pole figure (IPF) maps (Figure 1). Through EBSD analysis it was observed that the external surface of the film presents a strong texture on the basal plane orientation (grains highlighted in red colour). Furthermore it was possible to verify that the grain size strongly depends on the deposition time (Figure 1 (a) and (b)). The electrical and optical film properties improve with increasing of the grain size, which can be mainly, attributed to the decrease in scattering grain boundaries which leads to an increasing in carrier mobility (Figure 2).The authors kindly acknowledge the financial support from the Portuguese Foundation for Science and Technology (FCT) scientific program for the National Network of Electron Microscopy (RNME) EDE/1511/RME/2005.


2000 ◽  
Vol 6 (S2) ◽  
pp. 940-941
Author(s):  
A.J. Schwartz ◽  
M. Kumar ◽  
P.J. Bedrossian ◽  
W.E. King

Grain boundary network engineering is an emerging field that encompasses the concept that modifications to conventional thermomechanical processing can result in improved properties through the disruption of the random grain boundary network. Various researchers have reported a correlation between the grain boundary character distribution (defined as the fractions of “special” and “random” grain boundaries) and dramatic improvements in properties such as corrosion and stress corrosion cracking, creep, etc. While much early work in the field emphasized property improvements, the opportunity now exists to elucidate the underlying materials science of grain boundary network engineering. Recent investigations at LLNL have coupled automated electron backscatter diffraction (EBSD) with transmission electron microscopy (TEM)5 and atomic force microscopy (AFM) to elucidate these fundamental mechanisms.An example of the coupling of TEM and EBSD is given in Figures 1-3. The EBSD image in Figure 1 reveals “segmentation” of boundaries from special to random and random to special and low angle grain boundaries in some grains, but not others, resulting from the 15% compression of an Inconel 600 polycrystal.


2010 ◽  
Vol 638-642 ◽  
pp. 2841-2845 ◽  
Author(s):  
Ya Wen Lin ◽  
Jui Chao Kuo ◽  
Kuan Tai Lui ◽  
Delphic Chen

For interconnect materials in the microelectronic technology copper has replaced aluminum due to its lower resistivity, higher thermal conductivity and better electromigration resistance. Recently, it was found that nanotwinned copper exhibits ultra high yield strength, ductility and electrical conductivity. Therefore, in this study the effect of plating current density and frequency were investigated on the crystallographic texture of Cu electrodeposited to understand the twin character. Electron backscatter diffraction (EBSD) was used for characterizing the preferred orientation, grain size distribution, and grain boundary character distribution. Three kinds of <110>, <111> and <112> textures were found to be related with the electrodeposited parameters of current density and frequency. Here we will discuss the relationship between the preferred orientation and the electrodeposited parameters.


2020 ◽  
Vol 56 (9) ◽  
pp. 5845-5867
Author(s):  
Itziar Serrano-Munoz ◽  
Tobias Fritsch ◽  
Tatiana Mishurova ◽  
Anton Trofimov ◽  
Daniel Apel ◽  
...  

AbstractThe relationship between residual stresses and microstructure associated with a laser powder bed fusion (LPBF) IN718 alloy has been investigated on specimens produced with three different scanning strategies (unidirectional Y-scan, 90° XY-scan, and 67° Rot-scan). Synchrotron X-ray energy-dispersive diffraction (EDXRD) combined with optical profilometry was used to study residual stress (RS) distribution and distortion upon removal of the specimens from the baseplate. The microstructural characterization of both the bulk and the near-surface regions was conducted using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). On the top surfaces of the specimens, the highest RS values are observed in the Y-scan specimen and the lowest in the Rot-scan specimen, while the tendency is inversed on the side lateral surfaces. A considerable amount of RS remains in the specimens after their removal from the baseplate, especially in the Y- and Z-direction (short specimen dimension and building direction (BD), respectively). The distortion measured on the top surface following baseplate thinning and subsequent removal is mainly attributed to the amount of RS released in the build direction. Importantly, it is observed that the additive manufacturing microstructures challenge the use of classic theoretical models for the calculation of diffraction elastic constants (DEC) required for diffraction-based RS analysis. It is found that when the Reuß model is used for the calculation of RS for different crystal planes, as opposed to the conventionally used Kröner model, the results exhibit lower scatter. This is discussed in context of experimental measurements of DEC available in the literature for conventional and additively manufactured Ni-base alloys.


Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
Íris Carneiro ◽  
Filomena Viana ◽  
Manuel F. Vieira ◽  
José Valdemar Fernandes ◽  
Sónia Simões

This research focuses on the characterization of a metal matrix nanocomposite (MMNC) comprised of a nickel matrix reinforced by carbon nanotubes (CNTs). The aim of this study was to characterize Ni–CNTs nanocomposites produced by powder metallurgy using ball-milling. CNTs were initially untangled using ultrasonication followed by mixture/dispersion with Ni powder by ball-milling for 60, 180, or 300 min. The mixtures were cold-pressed and then pressureless sintered at 950 °C for 120 min under vacuum. Their microstructural characterization was mainly performed by optical microscopy (OM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). The mechanical properties were evaluated by Vickers microhardness. The results indicate that combining ultrasonication and ball-milling can successfully produce Ni–CNTs nanocomposites. The ball-milling time has a significant effect on both the CNT dispersion and the final nanocomposite microstructure.


2011 ◽  
Vol 689 ◽  
pp. 239-244
Author(s):  
Xiao Ying Fang ◽  
Xiao Cui ◽  
Cong Xiang Qin ◽  
Wei Guo Wang

A wedge-shaped 304 austenitic stainless steel with varied thickness longitudinally was cold rolled into a flat one and then annealed at 1323K for 10 min. The grain boundary character distributions (GBCDs) in the specimen as processed were examined by the means of Electron backscatter diffraction (EBSD). The results showed that, at the regions with low pre-strains ranged from 4% to 6%, quite high fractions of S3n (n=0,1,2,3) grain boundaries and large-sized S3n (n=0,1,2,3) grain clusters are introduced compared with the regions of quite low ( less than 2.5%) or relatively high pre-strain. The surface appearance of after corrosion test reveals that grain dropping due to intergranular corrosion (IGC) is depressed and the penetration of IGC from the surface into the interior in the cross-section is arrested significantly as well in the regions with high fractions of S3n boundaries and large-sized S3n grain clusters.


2008 ◽  
Vol 595-598 ◽  
pp. 409-418 ◽  
Author(s):  
L. Tan ◽  
Kumar Sridharan ◽  
T.R. Allen

Grain boundary engineering (GBE) was employed to improve the oxide exfoliation resistance and mitigate oxide growth by optimizing the grain boundary character distribution. Studies were performed on alloys of Incoloy 800H and Inconel 617. Alloys 800H and 617 were selected due to their potential applications for the Generation IV nuclear power systems. The effect of GBE on the corrosion response was evaluated using supercritical water exposure tests and cyclic oxidation tests. The microstructure of the tested samples was analyzed by means of optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, electron backscatter diffraction, and gravimetry. The effects of thermal expansion mismatch and Cr volatilization on the corrosion response are discussed.


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