A simple and inclusive method to determine the habit plane in transmission electron microscope based on accurate measurement of foil thickness

Abstract

A simple and inclusive method is proposed for accurate determination of the habit plane between bicrystals in Transmission Electron Microscope. Whilst this method can be regarded as a variant of surface trace analysis, the major innovation lies in the improved accuracy and efficiency of foil thickness measurement, which involves a simple tilt of the thin foil about a permanent tilting axis of the specimen holder, rather than cumbersome tilt about the surface trace of the habit plane.Experimental study has been done to validate this proposed method in determining the habit plane between lamellar  2 plates and  matrix in a Ti-Al-Nb alloy. Both high accuracy (1) and high precision (1) have been achieved by using the new method. The source of the experimental errors as well as the applicability of this method is discussed. Some tips to minimise the experimental errors are also suggested.

A general and robust analytical method for interface normal determination in TEM

“…(4) edge-on condition 3 projection width [13] holder Eq. (4) tilting about the trace 2 projection width [14] holder Eq. In the double-trace method and edge-on methods, the interface normal is always derived by the cross product of two vectors.…”

“…Qiu and Zhang [14] extended this work using the latter assumption, but they substituted √ 1 − e ⋅ 2 by taking the tilting axis of the sample holder as a reference vector. The derivation of this method using the present geometry model is given in Appendix C.…”

“…But it is usually difficult to ensure the tilting axis exactly parallel with the trace direction. Qiu an Zhang [14] solved this problem on a single tilt holder by taking the angle between the trace and the tilting axis into consideration. In order to avoid ambiguous solutions, this approach still needs to track the trend of the projection width change during sample tilting.…”

“…To improve the reliability, one may use excessive experimental data to calculate several solutions of the interface normal. The scattering of results can be plotted in a pole figure [12] [14], but the selection of the final result and the estimation of its uncertainty are largely based on the operator's experience.…”

pycotem: An open source toolbox for online crystal defect characterization from TEM imaging and diffraction

“…Analysing interface planes or dislocation slip planes also requires a lot of sample tilting. Though algorithms were developed, 21–23 not many software tools were reported on this purpose. ompas 15 offers a user‐friendly tool to identify the plane from its projections, but a priori guess of plane indices is still needed.…”