Electron Backscatter Diffraction. Characterization of Polyphase Materials

1999 ◽  
Vol 5 (S2) ◽  
pp. 262-263
Author(s):  
A. Medevielle ◽  
I. Hugon ◽  
O. Dugne

Electron diffraction was observed in 1928 by Kikuchi. In electron diffraction, diagrams characteristic of the crystal lattice and the phase orientation are formed. Consequently, Venable, then Dingley recently developed electronic diffraction coupled with scanning electron microscopy. Their approach enables micrometric scale examination of a specimen obtained by simple metallographical preparation (polished surface). Since the 1980’s, this technique has benefited from strong technological and computerized development which have led to the sale of the first systems under the name of Electron Backscatter Diffraction (EBSD). Niobium is used in the cast industry of uranium to refine it (getter function). The strong affinity of niobium for carbon leads indeed to the formation of small precipitates of niobium carbides. Whereas carbon cannot be detected by EDS because of its high absorption by the niobium (absorption coefficient μ=29000), hardness measurement indicates the presence of carbides (HV30 = 2000), but without further information on the nature of those carbides.

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.


2014 ◽  
Vol 782 ◽  
pp. 594-597
Author(s):  
Agnieszka Kochmańska ◽  
Paweł Kochmański

Nickel superalloy was coated by aluminide coatings by the slurry method. The slurry as active mixture containing aluminium and silicon powders, an activator and a binder. The coating were obtained by annealed in argon atmosphere. The structure of these coatings is two zonal and depends on time and temperature of producing. The phase composition was determined using following techniques: scanning electron microscopy (SEM) equipped with Xray microanalysis (EDS) combined with electron backscatter diffraction (EBSD) and Xray diffraction (XRD).


Author(s):  
C. Stallybrass ◽  
A. Völling ◽  
H. Meuser ◽  
F. Grimpe

In recent years, large-diameter pipe producers around the world have witnessed a growing interest to develop gas fields in arctic environments in order to fulfill the energy demand. High-strength linepipe grades are attractive for economic reasons, because they offer the benefit of a reduced wall thickness at a given operating pressure. Excellent low-temperature toughness of the material is essential under these conditions. Modern high-strength heavy plates used in the production of UOE pipes are produced by thermomechanical rolling followed by accelerated cooling (TMCP). The combination of high strength and high toughness of these steels is a result of the bainitic microstructure and is strongly influenced by the processing parameters. For this reason, the relationship between rolling and cooling parameters of heavy plate production, the low-temperature toughness and the microstructure is at the center of attention of the development efforts at Salzgitter Mannesmann Forschung (SZMF) in collaboration Salzgitter Mannesmann Grobblech (SMGB). It has been shown previously that a variation of the processing parameters has a direct influence on the microstructure and correlates with mechanical properties that are accessible via small-scale tests. Modern characterization methods such as scanning electron microscopy in combination with electron backscatter diffraction have broadened our understanding of the underlying mechanisms and have helped to define processing conditions for the production of heavy plates with optimized low-temperature toughness in small scale tests. Within the present paper, the results of a recent laboratory investigation of the effect of a systematic variation of rolling parameters on the microstructure and low-temperature toughness of as-rolled and pre-strained Charpy specimens are discussed. In these trials, final rolling temperatures above the onset of the ferrite-austenite transformation and cooling stop temperatures above the martensite start temperature were selected. The microstructure of the plates was investigated by scanning electron microscopy and electron backscatter diffraction. In a series of Charpy tests in a specific temperature range, it was found that plate material in the as-rolled condition is not strongly sensitive to variations of the selected processing parameters, whereas pre-straining the Charpy specimens made it possible to assess the potential of individual processing concepts particularly with regard to low-temperature toughness. In addition to Charpy testing, the toughness was also quantified via instrumented drop-weight tear (DWT) testing. By comparing total energy values from regular pressed-notch DWT-test specimens to J-integral values determined in drop-weight testing of pre-fatigued DWT-test specimens, the impact of variations of specimen type on material tearing resistance is shown.


2006 ◽  
Vol 15-17 ◽  
pp. 792-797 ◽  
Author(s):  
M.A.E. Jepson ◽  
C.L. Verona ◽  
R.L. Higginson

including, external oxide layers, internal grain boundary oxidation structures as well as many other forms of internal oxidation. During the present study, needle like grains of hematite have been observed within the top layers of a number of external oxide scales formed during simulated reheat of 316L stainless steel. It is believed that these needles are caused by the decomposition of an iron rich spinel (approximated to magnetite) along a preferred crystal direction within the spinel grains. The needles have been studied using optical microscopy, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD).


2008 ◽  
Vol 23 (7) ◽  
pp. 1877-1881 ◽  
Author(s):  
Ying-Ta Chiu ◽  
Kwang-Lung Lin ◽  
Yi-Shao Lai

Microstructural evolution occurred in 5Sn–95Pb/63Sn–37Pb composite flip-chip solder bump during electromigration. Scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) observations for 5Sn–95Pb/63Sn–37Pb composite flip-chip solder joints subjected to 5 kA/cm2 current stressing at 150 °C revealed a gradual orientation transformation of Pb grains from random textures toward (101) grains. We proposed that the combination of reducing the surface energy of Pb grain boundaries and resistance of the entire polycrystalline system are the driving force for the orientation transformation of Pb grains during an electromigration test.


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