Relation between applied stress and orientation relationship of α′ martensite in stainless steel single crystals
1974; University of Toronto Press; Volume: 22; Issue: 3 Linguagem: Inglês
10.1016/0001-6160(74)90170-9
ISSN1878-0768
AutoresYakichi Higo, Francis Lecroisey, T. Mori,
Tópico(s)Hydrogen embrittlement and corrosion behaviors in metals
ResumoAbstract Directional external stress was applied on single crystals of an Fe-17.7% Cr-13.6% Ni alloy to induce martensitic transformation. Using electron microscopy, orientations and locations of individual α′ martensite variants were determined. The relative population of the α′ variants, which all had orientations close to the Kurdjumov-Sachs orientation, was found to depend strongly on the direction and sense of the applied stress as well as on the temperature. The observed frequency of the various α′ variants was explained by postulating that the critical atomic movement to initiate α′ martensite formation was the shear along the {111}f 〈211〉)f direction and the following successive stages of the atomic displacement would then proceed spontaneously. Occurrence of twin-related α′ pair formation was frequent. Based on the above postulate, a component of a pair was shown to have such an orientation that its initiation was aided by the applied stress and the other component was identified as a variant produced under the influence of the internal stress of the former. The influence of the applied stress on the distribution of α′ martensite was most prominent at the Md temperature. Difference in the Md temperatures between tensile and compressive loadings was also explained by considering the magnitude of the Schmid factor on the {111}f 〈211〉f systems.
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