高温浸炭によりFe-3%Si合金単結晶{110}表面に析出したドーナツ状のセメンタイト

Abstract

High temperature carburization was done using the {110} surface of an Fe-3%Si single crystal. The carbide morphology of specimen surface was observed by the scanning and transmission electron microscopes.Doughnut-like cementite (Fe3C) of 50-200 nm in carburizing temperatures of 1173-1273K was formed on the {110} surface of an Fe-3%Si single crystal, and they formed with the colonies of the fine particles of about 2-5 nm. The preferential formation of Fe3C was quite different from the graphite formation that occured only under the high temperature carburization of past experiments.The orientation relationship between the Fe3C and iron matrix is considered to be [002]Cementite//[011]Fe. This relationship was consistent with that observed in the precipitation of Fe3C during the tempering of steel by Nishida and Tanino.It is considered that the {110} surface of an Fe-3%Si single crystal under the high temperature carburization formed with characteristic morphology of doughnut-like Fe3C, due to the preferential formation of the coherency for the crystallographic plane of (011)Fe and (002)Cementite.