| Fe-Ni-C alloys with Ms temperature of -28℃ were prepared by a high frequency induction furnace. Carbon content ranged from zero to 0.33 wt. % and nickel content was varied in accord with the above Ms temperature. Then the effects of deformation degree and carbon content on austenite stabilization of these alloys were investigated. When the austenite structures of Fe-Ni-C alloys were subjected to deformation at room temperature, the retained austenite content in martensite structure transformed from the austenite was increased with increasing deformation degree, and the increase in retained austenite content, at the same levels of deformation degree, became greater with increasing carbon content. In martensites obtained from reverted austenites of these alloy, prior martensites of which were subjected to deformation at room temperature, the retained austenite content was also increased with increasing deformation degree but the increase in retained austenite content at the same levels of deformation degree showed a same value, independent of carbon content. From the comparison between the above two results, it could be concluded that the reverted austenite transformed from deformed martensite is more stabilized in subsequent martensite transformation than the deformed normal austenite, at all deformation degrees. |
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