Abstract
The effect of a fine lamellar structure due to deformation twin on the yield strength of fcc ferrous alloys has been investigated by using cold-rolled Fe-36mass%Ni alloy and 310S stainless steels. Microstructural evolution during cold-rolling of both alloys has been also examined by using transmission electron microscopy. In cold-rolled Fe-36mass%Ni alloy, a kind of layered cell structure was observed, but no deformation twin was found. On the other hand, in a 310S steel, a fine lamellar structure of twin-matrix (T-M) was markedly developed with cold-rolling. The cold-rolled 310S steels exhibited yield strengths about 2 times higher than those of the rolled Fe-Ni alloys in spite that the yield strength of as-annealed 310S is lower than that of as-annealed Fe-Ni alloy. This indicates that the occurrence of fine T-M lamellae during cold-rolling enhances the evolution of fine-grained structure, which causes the marked increase in the yield strength of the rolled specimens.
