Real Time Observation of strain in the SEM copper sample

0567515 - ÚPT 2023 CZ eng A - Abstrakt
Piňos, Jakub - Frank, Luděk
Real Time Observation of strain in the SEM copper sample.
16th Multinational Congress on Microscopy, 16MCM, 04-09 September 2022, Brno, Czech Republic. Book of abstracts. Brno: Czechoslovak Microscopy Society, 2022 - (Krzyžánek, V.; Hrubanová, K.; Hozák, P.; Müllerová, I.; Šlouf, M.). s. 351-352. ISBN 978-80-11-02253-2.
[Multinational Congress on Microscopy /16./. 04.09.2022-09.09.2022, Brno]
Grant ostatní: AV ČR(CZ) StrategieAV21/26
Program: StrategieAV
Institucionální podpora: RVO:68081731
Klíčová slova: SEM * SLEEM * deformation
Obor OECD: Materials engineering
https://www.16mcm.cz/wp-content/uploads/2022/09/16MCM-abstract-book.pdf

The scanning electron microscope (SEM) with various detector arrangements and analytical attachments is an irreplaceable tool in material research. One of the techniques available in most
of contemporary microscopes is the scanning low energy electron microscopy. The beam deceleration allows controlling the information depth of the backscattered electrons (BSE) imaging
within a wide range by altering the landing energy of electrons. The BSE micrographs show, among others the crystallographic contrast of the grains in polycrystals. Relaxed samples show a homogeneous signal intensity within a grain, while in heavily deformed samples gradual signal variations appear even inside single grain. Previous experiments on heavily deformed samples shows effect of deformation in microstructure of the samples. We may ask how intense deformation is necessary to get visible effects in microstructure and whether this effect could be used to estimate the intensity of deformation. Using an in-situ tensile tester, the microstructure can be observed during the process. Thermo Fisher Scientific Scios SEM with Trinity detection system allows to use low landing energy and simultaneously obtain SE and BSE images. The Scios column uses a biased A-tube to form a high energy primary beam and then decelerate to the required energy for observation. Signal electrons are detected by various detectors: ETD – standard SE detector, T1 – in-column, closest to the polepiece, detecting high-angle BSE T2 – in-column, higher in column detecting the low-angle BSE. The observations were performed in the Optiplan mode at a working distance of 6.25 mm, using a landing energy of 2keV and an A-tube bias of 8 kV. The beam current was set as 1.6 nA. Fig 1. shows images taken by the ETD, T1 and T2 detector and its changes from as inserted state to just before breakage. The effect of deformation on the crystalline structure is most visible in the images obtained by the T1 detector. This in-column detector collects mostly high-angle BSE electrons, which provide crystallographic information. During the elastic deformation phase, the microstructure of the sample remains the same. The tensile test graph is shown in Fig. 2. The first observable changes in the microstructure starts to appear at a stress of about 120 MPa – the corresponding plastic deformation of about 4%. The development of the effect continued in Fig. 3. However, accurate quantification was not possible. We can conclude that deformations exceeding 5% can be identified in the microstructure.
Trvalý link: https://hdl.handle.net/11104/0338768