Yukio Inokuti1, Yutaka Ono2 and F. Eiichi Fujita3
1Graduate Student, Osaka University, Toyonaka
In the previous work(1), we have shown, as one of the results, that in super purity α-iron the precipitation curves of super-saturated carbon measured by electrical resistivity are noticeably delayed from those measured by internal friction while they are not appreciably different from each other in the commercially pure iron which usually contains a small amount of oxygen.
This delay was considered to be arising from an extraordinarily large scattering of conduction electrons from the precipitate particles in the super purity α-iron. On the other hand, there exsisted some doubt if this phenomenon was due to the effect of dislocations; that is, dislocations in the purer specimens might gather more precipitant carbon atoms than in the less pure specimens accelerating the precipitation process and at the same time, form a special configuration of precipitates or agglomeration which has a large scattering power for electrons. Therefore, the precipitation process of carbon in the super pure specimens with a considerably high density of dislocations was examined by the electrical resistivity and internal friction changes.
The specimens containing about 0.009 wt% carbon were cold-worked to 5% extension after quenching and the precipitation process was followed by the electrical resistivity and internal friction measurements during 132°C isothermal annealings. The precipitation curves obtained by both methods coincide with each other within experimental errors. From this result, we conclude that the scattering of conduction electrons by the precipitates at the dislocation sites must be different in the reversed sense from that of the precipitates in the matrix of super purity α-iron.
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