-

Electron Backscattered Diffraction (EBSD)

The electron backscattered diffraction (EBSD) is a very powerful tool for material science. Accelerated electrons in the primary beam of a scanning electron microscope (SEM) can be diffracted by atomic layers in crystalline materials. These diffracted electrons can be detected when they impinge on a phosphor screen and generate visible lines, called EBSP (electron backscatter patterns). These patterns are effectively projections of the geometry of the lattice planes in the crystal [1], and they give direct information about the grain size of purity bismuth crystal. Analyzing grain size of a bismuth crystal is important for quality control. When a metal or alloy is processed, the atoms within each growing grain are lined up in a specific pattern, depending on the crystal structure of the sample.[2]

^{Through the calculation of the average value, we can use computer software or direct measurement to obtain qualitative information about the grain size of the bismuth crystal. Furthermore, the image shows that with the time of annexed deformation increasing, the grain size of 20% Bi2Te3-80% Sb2Te3 alloys also increases.}

^{For the crystal orientation, the parts of the same color represent the same crystal orientation, which is shown in the images.}

Fig. 1. EBSD images of mechanically deformed 20% Bi₂Te₃-80% Sb₂Te₃ alloys annealed at 380°C [3]

Fig. 2 shows the EBSD chrysanthemum-like image of BSCCO (Bi-Sr-Ca-Cu-Co), which is an EBSD feature image detected based on SEM technology. We can use computer software technology to convert the chrysanthemum-like image into a color image containing grain size and grain oritation, and then detect more about the nature of the material.

4.png.1

Fig. 2. EBSD chrysanthemum-like image of BSCCO (Bi-Sr-Ca-Cu-Co) [4]

Fig. 3 shows that EBSD image of the Sn-Bi alloy with the detected grain size. At the same time, we can conclude that in Sn-Bi alloys based on Sn, as the content of Bi gradually increases, the grain size of the alloy gradually decreases.

6.png.1

Fig. 3. Grain size observations of as-plated films using FIB microscopy: (a) pure Sn (b) Sn-0.5Bi (c) Sn-1Bi, and (d) Sn-2Bi [5]

Fig. 4(a) shows the EBSD microstructure reconstruction of the longitudinal section (along the extrusion direction) of the extruded BAZ711 alloy. It can be seen from Fig. 5(a) that the extruded alloy is completely recrystallized, with an average grain size of about 2.9 μm. [6]

5.png.1

Fig. 4. EBSD analysis of as-extruded BAZ711 alloy: (a) EBSD orientation map; (b) Inverse pole figure [6]

References:

[1] Geochemical Instrumentation and Analysis. Electron Backscatter Diffraction (EBSD). [R/EB]. [2020-06-03.] https://serc.carleton.edu/research_education/geochemsheets/ebsd.html.

[2] Olympus Industrial Resources. Application Notes. Grain Size Analysis in Metals and Alloys. [Z/EB]. [2020-06-03.] https://www.olympus-ims.com.cn/en/applications/grain-size-analysis/.

[3] ResearchGate. EBSD images of mechanically deformed 20%Bi₂Te₃-80%Sb₂Te₃ alloys [R/EB]. [2020-06-04.] https://www.researchgate.net/figure/EBSD-images-of-mechanically-deformed-20Bi-2-Te-380Sb-2-Te-3-alloys-annealed-at-380C_fig1_262953746.

[4] EDAX.AMETEK.MATERIALS ANALYSIS DIVISION. [R/EB]. [2020-06-09]. https://www.edax.com/resources/interactive-periodic-table/bismuth.

[5] ResearchGate. Mitigation of Sn Whisker Growth by Small Bi Additions. [R/EB]. [2020-06-09]. https://www.researchgate.net/publication/260723436_Mitigation_of_Sn_Whisker_Growth_by_Small_Bi_Additions.

[6] Meng Shua-ju, YU Hui, CUI Hong-wei, ZHANG Jing, ZHAO Wei-min, Wang Zhi-feng, QIN Chun-ling. Microstructure and mechanical properties of a new mG-Bi-al-Zn deformed magnesium alloy [J]. The Chinese Journal of Nonferrous Metals. [2020-06-09]. DOI：10.19476/j.ysxb.1004.0609.2017.05.003

Relevant Links

Relevant Links

Characterisation Data of Bismuth

Confirm copying

Restore backup