High Strength Materials Group

Microstructural effects on the mechanical properties are deeply associated with the deformation behavior in the same scale of the microstructures. In the conventional approach is limited to post-deformation observation and speculation of the deformation mechanisms. We use a new technique of nano-scale mechanical characterization to reveal the elementally step of deformation behavior. A continuum mechanics simulation is also applied to predict the macroscopic mechanical properties from the nano-scale deformation behavior. We target metals including steels and try to understand the effects of lattice defects such as dislocations, grain boundaries, solute elements and second phase inclusions to the mechanical properties. We are going for establishing a new guide principle of materials design through the interpretation of the relationship between the microstructures and the mechanical properties.

Specialized Research Field

1. Nanoscale mechanical characterization

A feature of our approach is a direst mechanical characterization using nanoindentation technique to analyze quantitatively the deformation behavior in nano-scale to reveal the relationship between the microstructure and mechanical response. Through the unique methods, we can pick out the deformation behavior of grain interior even though a grain size is different and evaluate the effect of single grain boundary. By separating the several microstructural effects, we are closing to the deformation mechanisms.

2. In-situ deformation analysis in a TEM

In-situ nanoindentation in a TEM is applied as a noble technique to analyze the deformation behavior in nano-scale. This technique allows us to observe the dynamic microstructural change during deformation and evaluate the load-displacement data simultaneously; hence the microstructural evolution and the corresponding mechanical behavior can be directly analyzed.

3. Multiscale analysis of plastic deformation behavior

The macroscopic mechanical behavior comes out through the superposition and interaction of various microstructure-mechanics relations. We are trying to predict the macroscopic mechanical behavior of materials with fine microstructures through the continuum element model in multi-scale up to high strain level.

Group Leader

"Takahito OHMURA" Image

Takahito OHMURA

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High Strength Materials Group
1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, JAPAN
E-Mail: OHMURA.Takahito=nims.go.jp(Please change "=" to "@")
National Institute for Materials Science (NIMS)
1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, JAPAN