| 1. |
- Lozinko, Adrianna, 1992, et al.
(author)
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Quantification of microstructure in a eutectic high entropy alloy AlCoCrFeNi2.1
- 2019
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In: IOP Conference Series: Materials Science and Engineering. - 1757-8981 .- 1757-899X. ; 580:1
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Conference paper (peer-reviewed)abstract
- Eutectic high entropy alloys (EHEAs) are a new class of metallic alloys with good mechanical properties at various temperatures. In the present investigation, microstructural parameters such as the volume fraction of two phases (FCC (L12) and BCC (B2)) forming the eutectic, the orientation relationship between these phases and interphase boundary spacings in as-cast EHEA AlCoCrFeNi2.1 were quantified using electron microscopy. It is found that the two phases have a Kurdjumov-Sachs orientation relationship, i.e., {111} fcc || {110} bcc and 〈110〉 fcc || 〈111〉 bcc . It is also found that both regular semi-coherent lamellar and irregular curved interphase boundaries are present within individual eutectic colonies. The habit planes for the semi-coherent lamellar interfaces are {224} and {123} for the FCC and BCC phases, respectively. Quantitative microstructural analysis shows that the ratio of volume fractions of the FCC and BCC phases within the regular lamellar regions differs to that within irregular regions, which suggests a local chemistry difference between the two regions. Finally, the solidification process of EHEAs is discussed, and possible ways to optimize the mechanical properties by microstructural design are suggested.
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| 2. |
- Sun, Jun, et al.
(author)
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3D characterization of partially recrystallized Al using high resolution diffraction contrast tomography
- 2018
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In: Scripta Materialia. - : PERGAMON-ELSEVIER SCIENCE LTD. - 1359-6462 .- 1872-8456. ; 157, s. 72-75
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Journal article (peer-reviewed)abstract
- Synchrotron diffraction contrast tomography (DCT) is for the first time used to characterize recrystallized grains in partially recrystallized Al. The positions, orientations and 3D shapes of amp;gt;900 recrystallized grains are reconstructed within a gauge volume. The results are compared with those obtained using electron backscattered diffraction based on a statistical analysis. It is found that recrystallized grains with size larger than 10 mu m, corresponding to similar to 98% of the total recrystallized volume of the sample, are well characterized by DCT. The advantages of DCT for recrystallization studies and new possibilities with DCT on new generation synchrotron sources are discussed. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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| 3. |
- Zhang, Yubin, et al.
(author)
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Stress relief during annealing of railway wheel steel characterized by synchrotron X-ray micro-diffraction
- 2022
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In: 42nd Risø International Symposium on Materials Science. - : Institute of Physics Publishing (IOPP). ; 1249
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Conference paper (peer-reviewed)abstract
- Railway wheels in service experience rolling contact fatigue loading, but also need to resist frictional heating on braking, yielding temperatures up to 500 degrees C. The combination of mechanical and thermal loads leads to changes in the mechanical properties of the material. The focus of this study is to investigate the effect of annealing on local microstructure and residual stresses in railway wheel pearlitic steel (medium carbon steels, similar to 0.55 wt.% C) using synchroton X-ray Laue micro-diffraction. It is found that the local residual stress releases to a large extent after annealing at 500 degrees C. The stress formation and relief mechanisms and their relationship to the local microstructure are discussed.
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