TEM in situ cube-corner indentation analysis using ViBe motion detection algorithm

JOURNAL OF NUCLEAR MATERIALS

卷:502

Article

Yano, K. H.¹  Thomas, S.²  Swenson, M. J.³  Lu, Y.²  Wharry, J. P.¹ 

[1] Purdue Univ, 400 Cent Dr, W Lafayette, IN 47907 USA

[2] Boise State Univ, 1910 Univ Dr, Boise, ID 83725 USA

[3] Univ Idaho, 875 Perimeter Dr, Moscow, ID 83844 USA

关键词: Ion irradiation;    Oxide dispersion strengthened;    In situ;    Indentation;    Picoindenter;    TEM;    TEM mechanical testing;   

DOI  :  10.1016/j.jnucmat.2018.02.003

来源: Elsevier

【 摘 要 】

Transmission electron microscopic (TEM) in situ mechanical testing is a promising method for understanding plasticity in shallow ion irradiated layers and other volume-limited materials. One of the simplest TEM in situ experiments is cube-corner indentation of a lamella, but the subsequent analysis and interpretation of the experiment is challenging, especially in engineering materials with complex microstructures. In this work, we: (a) develop MicroViBE, a motion detection and background subtraction-based post-processing approach, and (b) demonstrate the ability of MicroViBe, in combination with post-mortem TEM imaging, to carry out an unbiased qualitative interpretation of TEM indentation videos. We focus this work around a Fe-9% Cr oxide dispersion strengthened (ODS) alloy, irradiated with Fe2+ ions to 3 dpa at 500 degrees C. MicroViBe identifies changes in Laue contrast that are induced by the indentation; these changes accumulate throughout the mechanical loading to generate a heatmap of features in the original TEM video that change the most during the loading. Dislocation loops with b = 1/2 < 111 > identified by post-mortem scanning TEM (STEM) imaging correspond to hotspots on the heatmap, whereas positions of dislocation loops with b = < 100 > do not correspond to hotspots. Further, MicroViBe enables consistent, objective quantitative approximation of the b = 1/2 < 111 > dislocation loop number density. Published by Elsevier B.V.

【 授权许可】

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