Effect of magnetic field on TTT diagram of successive γ→ε'→α' martensitic transformation in SUS304L stainless steel

We have investigated the effect of magnetic field on TTT diagram of successive γ→ε'→α' martensitic transformation in a solution-treated SUS304L stainless steel in order to clarify kinetics of the successive martensitic transformation. The TTT diagram of successive γ→ε'→α' martensitic transformation shows a C-curve with a nose temperature located at 103 K. Incubation time of the successive γ→ε'→α' martensitic transformation shortens with increasing the strength of magnetic field. However, the nose temperature does not change significantly under the magnetic field. An in-situ optical micrograph suggests that the successive γ→ε'→α' transformation probably proceeds by isothermal γ→ε' martensitic transformation followed by athermal ε'→α' martensitic transformation.