Analysis on Determination of Correct Solutions in Orientation Imaging Microscopy

DE VINCENTIS, N.S.; FIELD, DAVID P.

Buenos Aires

Congreso; XV Congreso Interamericano de Sociedades de Microscopía CIASEM-SAMIC; 2019

EBSD is a widely used technique that that allows to determine the crystallographic orientation ineach point of a scanned surface [1] by measuring and indexing Kikuchi patterns. A triplet votingmethod can be defined [2], in which a particular orientation can be determined using a triplet ofKikuchi bands and associating to it a Confidence Index (CI). In previous work, it has been observedthat the use of six Kikuchi bands lead to obtain the correct solution about 95% of the times with a CIof 0.1 in single crystal Si [3]. The present study extends the analysis to explore the influence of otherfactors on the correctness of the determined orientation such as crystallographic structure andorientation. With this goal, EBSD patterns of single crystal Si and polycrystalline Zn were collectedand re-processed using different number of bands, and the relationship between the correctness ofsolutions and CI was inspected.The Inverse Pole Figure maps and fraction of correct solutions obtained Si are presented in Fig. 1. Itcan be observed that the fraction of correct solutions increases with the number of Hough bands usedfor indexing for each CI, and that for a CI value of 0.1 about 90% of solutions correspond to thecorrect orientation when at least 8 Hough bands are used. The results shown in Fig. 2 for Zn are quitesimilar to those obtained for Si, where higher number of bands resulted in a larger fraction of correctsolutions for lower CI values, and in this case a 90% of correct results at a CI of 0.1 was reached for6 bands, while over 95% of correct solutions were obtained with 8 bands. [4]References:[1] A.J. Schwartz, M. Kumar, B.L. Adams, D.P. Field, Electron Backscatter Diffraction in MaterialsScience, 2nd ed. Kluwer Academic-Plenum Publishers, New York (2000).[2] S.I. Wright, PhD Thesis, Yale University (1992).[3] D.P. Field, Ultramicroscopy 67 (1997), p. 1.[4] The authors acknowledge the Fulbright commission.