Yielding Behavior of Ultralow Carbon Martensitic Steel and Its' Change by Cold-working or Tempering

摘要

Lath martensite in steel has a high dislocation density of approximately 10~(15)/m~2, which corresponds to that of heavily deformed ferritic irons. However, the distribution of dislocations in the martensitic structure differs from that in the deformed ferritic structure; dislocations are heterogeneously dispersed in the cold-worked ferritic steels (dislocation cell structure), while those in martensitic steels are uniformly dispersed within the matrix. On the other hand, it is also reported that the dislocation substructure of martensite significantly changes by cold-rolling of 10 percent reduction in thickness. In this study, the yielding behavior and its change by cold-working or tempering were investigated in ultralow carbon martensitic steel, and then the effect of dislocation distribution on the yielding behavior was discussed.