This study demonstrates the mechanism of y ? a transformation in creep test on the basis of the energy o f the system. The experimental result shows that the strain energy around M23Co carbide becomes very high due to dislocations stored during creep. As a result, the system free energy in the local region near the carbide increases with increasing creep time but it decreases by the formation of ferromagnetic a phase....
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Formation of ferromagnetic phase in SUS304 steel by strain energy stored during creep test

The formation of the ferromagnetic a phase during creep deformation in SUS304 steel was simulated by a hase-field method. In order to consider the precipitation and growth of the phase simultaneously, we have onstru cted a model based on experimental results. In this model, strain energy stored near M23Co carbide uring creep deformation increases the driving force for precipitation of the a phase. This strain energy is stimated on the basis of distribution function of dislocation density in space near the ...
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Phase-field simulation on the formation of ferromagnetic phaseduring creep deformation in SUS304 steel

Microstructural state of metallic materials can be expressed by the system free energy, and the estimation of the system free energy is useful for the damage analysis of the materials. In this study, change in the system free energy of 9Cr heat resistant ferritic steels is estimated with cre ep time on the basis of Thermo-Calc calculation as well as a series of experiments such as X ray diffraction analysis, chemical analysis using ext racted residues, etc., and the change with creep time is expressed quan...
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Change in the system free energy of 9Cr heat resistant ferritic steels with creep time

State of microstructure in metallic materials can be expressed as numerical values based on a concept of system free energy, and the energy value is used as a measure of damage analysis of the materials. In this study, change in the system free energy of the FG-HAZ in 9Cr heat resistant ferritic steels during creep is evaluated as summation of chemical free energy, strain energy and surface energy, which are obtained by a series of experiments, i.e., chemical analysis using extracted residues, X-ray d...
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Microstructural analysis of HAZ in the welded joints of 9Cr heat resistant ferritic steels for fast reactor

Microstructural states of metallic materials can be expressed by system free energy, and the estimation of the system free energy is useful for damage analysis of the materials. In this study, chang e with creep time in the system free energy of the FG-HAZ in 9Cr heat resistant ferritic steels is estimated on the basis of a series of experiments such as chemical analysis by using extracted resid ues, X-ray diffraction, and scanning transmission observations. The change in the system free energy is expresse...
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Microstructural analysis of HAZ in the welded joints of 9Cr heat resistantferritic steels for fast reactor