Dear colleagues,
I am wondering if any of you is familiar with using EBSD plane trace analysis function to determine activated slip systems in deformed metallic alloys (of course coupled with the micro-graphs of slip steps)?
It has appeared in the literature (see attachment) that such a procedure can be accomplished by overlapping the star-shaped plane traces of certain crystal planes on to the image quality map (or others). I am, however, wondering if this can give an one-by-one mapping of slip systems? And if so what are the underlying crystallographic principles it follows?
Many thanks for your kind help!
Dear Dr. Prof. Raabe:
Many thanks for your detailed response and for recommending these wonderful reference! I will try to figure out the experimental details following your guidance.
In light of the ECCI coupling technique you are referring to, I am always a bit confused about how to quantitatively find the "two-beam" condition under SEM so as to get the optimal channeling contrast?
Thanks a lot again and wish you a pleasant weekend!
Hi Shaolou,
I have done some slip trace analysis about HCP metals (Mg), and I am writing paper now. When you get the EBSD data, you can calculate every slip planes in three-dimensional space using the Euler angles. Then the theoretical directions for every planes on the sample surface could be calculated. By using the combination of EBSD data and SEM data with slip lines (compare the theoretical direction by EBSD calculation and actual direction by SEM), the closest theoretical direction will be selected as the activated slip system. In addition, the Schmid Factor will be used as an auxiliary condition.
I hope this helps. Attached are two related papers.
Dear Gaoming,
Thank you for your detailed answer and for suggesting these two helpful papers. I also look forward to your great work.
Have a nice day!
Dear Shaolou,
As we have frequently carried out such analysis, I would like to add a few words on limitations.
Firstly, only the slip plane can be determined using this technique. The slip direction is inferred. If several slip systems share the same slip plane, they will correspond to the same slip trace. For instance, this is the case for basal slip systems of HCP metals (our work mainly focusses on Ti alloys, for more information please refer to the attached files). In practice, the slip system with the highest Schmid factor is often assumed to be active.
Secondly, identification of slip planes relies on the comparison of experimental slip traces with theoretical slip traces. Indeterminations may result from close theoretical slip traces of different slip planes (this is quite frequent for prismatic and pyramidal plane traces in HCP metals such as Ti). An angular criterion (typically 5°) has to be introduced to obtain a rigorous analysis and limit any bias. The Schmid factor might be used as an indicator of slip activation likeliness but one has to be careful about the different CRSS magnitudes associated with the various slip modes.
I hope this helps!
Dear Samuel,
Many thanks for your detailed response and for sharing you wonderful work. I will certainly read through them.
One additional question here: as you specified that theoretical slip trace can be calculated by using Euler angles, I am a bit curious about the visualization of your calculation results. Did you accomplish this by external software or just using the plane trace analysis function in OIM?
Thanks for your kind help!
Shaolou,
I can share with you my tools to calculate the slip trace according to a given euler angles obtained from a given geometry for the EBSD measurements. Previously we have used the calculated crystallographic plane trace to identify the twinning or dislocation slip activities. Please see Fig.3d in paper: Q.Xie, J.Liang, A.D. Stoica, R. Li, P. Yang, Z. Zhao, J. Wang, H. Lan, R. Li, K. An, In-situ neutron diffraction study on the tension-compression fatigue behavior of a twinning induced plasticity steel, Scripta Materialia, 137, 83-87(2017).
and Fig.9a in paper: Q. Xie, Z.Pei, J.Liang, D.Yu, Z.Zhao, P.Yang, R.Li, M.Eisenbach, K.An, Transition from the twinning induced plasticity to the g-e phase transformation induced plasticity in a high manganese steel, Acta Materialia 161(2018) 273-284.
Qingge
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