The Laminated/Network Interface Design and Deformation Behavior of Multilayer Steel

The SUS304/45 multilayer steels with laminated/network coupling interfaces were fabricated by cold rolling, and the interface evolution behavior and strengthening-toughening mechanism were clarified by microstructure characteristics, tensile testing, and detailed finite element analysis. The results show that when the cold rolling reduction increases from 75 to 87.6 pct, the interface transitions from straight to wavy, and finally forms a laminated/network coupling interface (i.e., the reconstruction of the "Damascus pattern"). The coupling interface is attributed to the uncoordinated deformation of two constituent layers with different crystal structures and stacking fault energy during the cold rolling deformation process. The commercial finite element software ABAQUS was used to simulate the rolling process with different reduction ratios, and the formation mechanism of the laminated/network coupling interface structure is attributed to incoordination deformation of heterogeneous layers. The laminated/network coupling interface and deformation microstructure of constituent layers were further optimized by annealing treatment. The multilayer steel annealed at 700 degrees C for 30 minutes had the best strength-toughness combination, which is due to the synergistic effect of solid solution, grain refining, dislocation and heterogeneous deformation-induced strengthening. This work provides a novel design idea for strengthening-toughening multilayer steels.