Lan K-C, Zhong W, Mouche P A, Tung H-M, Lee H, Heuser B J, Stubbins J F
Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A.
Nuclear Fuels and Materials Division, Institute of Nuclear Energy Research, Longtan, Taoyuan, Taiwan, ROC.
J Microsc. 2018 Oct;272(1):25-34. doi: 10.1111/jmi.12729. Epub 2018 Jun 26.
This work presents a methodology combining SEM, EDS, conventional EBSD, and transmission-EBSD to analyse a recrystallised Zircaloy-4 sheet and cold-worked stress-relieved (CWSR) Zircaloy-4 cladding in unprecedented detail. Second-phase precipitates (SPPs) in Zircaloy-4 specimens were revealed after chemical polishing using a solution containing hydrofluoric acid (HF). Pitting corrosion of Zircaloy-4 specimens was revealed after electropolishing using an electrolyte containing HClO . A zirconium coupon without SPPs was used to confirm the chemical response of SPPs on surface morphology. Intrinsic features of cold-worked Zircaloy-4 such as relatively small grain sizes, high dislocation density, and complex microstructure make it significantly more difficult to collect excellent EBSD results compared to recrystallised Zircaloy-4. The fine hydride structure of as-hydrided CWSR Zircaloy-4 cladding further increases the level of challenge on EBSD analysis.
We present a methodology combining multiple microscopic methods to analyse a recrystallised Zircaloy-4 sheet and cold-worked stress-relieved (CWSR) Zircaloy-4 cladding, important alloys of structural materials widely used in nuclear application, and emphasis on the challenge of acquiring a satisfactory electron backscatter diffraction (EBSD) result of CWSR Zircaloy-4 cladding material in great details. EBSD is a powerful technique to characterise the crystallographic distribution and lattice type of conductive crystalline materials, especially for a highly textured material like CWSR Zircaloy-4 alloy. However, zirconium alloys are known to be one of the most difficult materials to prepare for EBSD characterisation. We point out that the configuration of the microstructure of the specimen cause the challenge in the EBSD sample preparations. Moreover, the occurrence of tiny zirconium hydride precipitates in Zircaloy-4 increases the difficulty. We believe that the information of the EBSD sample preparation related results in this paper can provide researchers and scientists in this community a useful reference to speed up the EBSD sample preparation of CWSR Zircaloy-4 cladding material and to expect the corresponding EBSD results.
本工作提出了一种结合扫描电子显微镜（SEM）、能谱仪（EDS）、传统电子背散射衍射（EBSD）和透射电子背散射衍射的方法，以前所未有的细节分析重结晶锆合金 - 4板材和冷加工应力消除（CWSR）锆合金 - 4包壳。使用含氢氟酸（HF）的溶液进行化学抛光后，揭示了锆合金 - 4试样中的第二相析出物（SPP）。使用含高氯酸（HClO）的电解液进行电解抛光后，揭示了锆合金 - 4试样的点蚀。使用无SPP的锆试样来确认SPP对表面形貌的化学响应。与重结晶锆合金 - 4相比，冷加工锆合金 - 4的固有特征，如相对较小的晶粒尺寸、高位错密度和复杂的微观结构，使得获取出色的EBSD结果要困难得多。氢化后的CWSR锆合金 - 包壳的精细氢化物结构进一步增加了EBSD分析的难度。
我们提出了一种结合多种微观方法的方法，以分析重结晶锆合金 - 4板材和冷加工应力消除（CWSR）锆合金 - 4包壳，这是广泛用于核应用的重要结构材料合金，并着重详细阐述了获取CWSR锆合金 - 4包壳材料令人满意的电子背散射衍射（EBSD）结果所面临的挑战。EBSD是一种强大的技术，可用于表征导电晶体材料的晶体学分布和晶格类型，特别是对于像CWSR锆合金 - 4合金这样具有高度织构的材料。然而，锆合金是已知最难制备用于EBSD表征的材料之一。我们指出，试样微观结构的形态给EBSD样品制备带来了挑战。此外，锆合金 - 4中微小氢化锆析出物的出现增加了难度。我们相信，本文中与EBSD样品制备相关的结果信息可以为该领域的研究人员和科学家提供有用的参考，以加快CWSR锆合金 - 4包壳材料的EBSD样品制备，并预期相应的EBSD结果。
