12/3 Seminar Speech

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Created on Tuesday, 27 November 2018 14:10

Last Updated on Monday, 03 December 2018 13:22

Published on Tuesday, 27 November 2018 14:11

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Speaker: Doctor Seiichiro Ii

Topic:Advantages of In-Situ TEM Technique for Materials Dynamics

Speaker：Doctor Seiichiro Ii

Organization：Research center for Structural Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan

Topic：Advantages of In-Situ TEM Technique for Materials Dynamics

Date：10:20 , 2018.12.3

Location：Room 203, College of Engineering

Abstract：

Understanding of dynamics of the materials behavior such as phase transformation, dislocation motion, fracture and so on, in-situ observation is one of powerful techniques. In this talk, I would like to introduce about past and current situation and the advantages of the in-situ TEM studies with our studies.

For example, crack propagation behavior in brittle ceramic materials is scientific and technological important, since the crack propagation determines fracture toughness and reliability of the materials. It can be expected that the crack propagation takes place by breaking individual atomic bonds in grain interior or grain boundaries, which will result in the formation of atomically-flat fractured surfaces and atomically sharp crack tips. Many of the experiments for the crack propagation behavior have been made for the specimens after crack generation. In other words, ex-situ experiments have been done. In ceramic materials, transmission electron microscopy (TEM) specimens have been prepared by ion-milling technique, so that the atomic structure around crack surface is changed during sample preparation process. [1-4]

Dislocation motion during plastic deformation in metals is also given in this seminar.

References

[1] S. Ii et al., Philos. Mag., 84, 2767 (2004)

[2] S. Ii et al., Appl. Sur. Sci., 241, 68 (2005)

[3] P. F. Becher et al., J. Am. Ceram. Soc., 88, 1222 (2005)

[4] S. Ii et al., J. Electron Microscopy, 53, 121 (2004)