Deformation-Induced Martensitic Transformation at Tensile and Compressive Deformations of High-Carbon Bainitic Steel

Deformation induced martensitic transformation during tensile or compressive deformation of the high-carbon bainitic steel (0.62wt%C-2.02%Si-0.23%Mn-1.01%Cr-Fe) was studied. The microstructure before the deformation was bainite with the retained austenite whose volume fraction was 35%. The tensile deformation is accompanied by more significant work hardening than that at the compression. This was due to the suppression of deformation induced martensitic transformation at the compression, which was confirmed mainly by the in situ neutron diffraction at TAKUMI, J-PARC. It was also found that the increasing lattice strain at austenite by tensile deformation retarded with the deformation-induced martensitic transformation, while this retardation was not found at the compression.