A Dislocation-Based Theory for the Deformation Hardening Behavior of DP Steels: Impact of Martensite Content and Ferrite Grain Size

Table 1

Summary of dislocation substructure development in a C-Mn-Si dual-phase steel in tension [14].

True plastic strain (%)	Typical ferrite dislocation substructures	Variation of the substructure within a typical ferrite grain
0	Very low average dislocation density	High dislocation density adjacent to martensite
1	No cells: a few straight, planar dislocation walls	Dislocation density higher near martensite
2	Incipient cells: many long, straight walls	Cell structure generally forms first near martensite
7	Well-developed cell structure; thick cell walls	Cell size smaller near martensite (~0.4 μm) than away from martensite (~0.7 μm)
14	Well-developed cell structure with many straight, thin cell walls	Cell sizes approximately the same as for 7 pct strain