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Discrimination of dynamically and post‐dynamically recrystallized grains based on EBSD data: application to Inconel 718
Author(s) -
NICOLAŸ A.,
FRANCHET J.M.,
CORMIER J.,
MANSOUR H.,
DE GRAEF M.,
SERET A.,
BOZZOLO N.
Publication year - 2019
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/jmi.12769
Subject(s) - electron backscatter diffraction , inconel , materials science , misorientation , dynamic recrystallization , recrystallization (geology) , smoothing , metallurgy , geology , microstructure , computer science , grain boundary , hot working , computer vision , paleontology , alloy
Summary The importance of angular resolution in EBSD analyses is discussed based on an Inconel 718 sample containing several populations of recrystallized grains, with subtle differences in dislocation contents. Classical EBSD analyses (with angular resolution in the range of 0.5–1°) do not allow for distinguishing recrystallized grains grown dynamically or post‐dynamically. The angular resolution of EBSD orientation and misorientation data can be significantly improved (down to about 0.1–0.2°) either using more sophisticated Kikuchi pattern indexing methods and/or using the recently proposed LLASS denoising filter (Local Linear Automatic Smoothing Splines). Then the coexistence of both dynamically and post‐dynamically recrystallized grains in the sample can be confirmed and quantified. ECCI images unambiguously confirm the conclusions drawn from the analysis of improved angular resolution EBSD data, and furthermore reveal the presence of thermal stress induced dislocations with typical patterns in water quenched Inconel 718 recrystallized grains. Lay Description EBSD is widely used to study recrystallization phenomena. Conventional EBSD is nevertheless not able to distinguish dynamic recrystallized grains from post‐dynamic recrystallized grains which differ by subtitle differences in dislocation contents. In this paper, we show that improving the orientation precision of EBSD data by means of different methods allows distinguishing these two recrystallized grains populations. Analyses and discussion are based on an Inconel 718, a famous Nickel‐based superalloy in aeronautic.