Interfacial fracture behavior of a stainless/carbon steel bimetal plate in a uniaxial tension test

The interfacial fracture behavior of a stainless/carbon steel bimetal plate in a uniaxial tensile test was investigated in this paper. The ultrasonic C-scan results showed that the internal fracture had already appeared in the necking area before the tensile sample snapped, and the internal fracture occurred in the middle of the necking area and propagated with the tensile strain increase. The fractography showed that the internal fracture occurred at the interface between the diffusion layer and carburization stainless steel. The contribution of the internal stress to the interface fracture was analyzed by finite element method. The FEM results showed that, due to the different material mechanical properties, the large stress difference between the diffusion layer and the carburized stainless steel induced the interface shear stress. The shear stress value was related to the location and tensile strain, and when the stress difference was larger than 500 MPa, the interface would crack. Keywords: Bimetal plate, Ultrasonic C-scan, Fracture analysis, Stress difference, Interface shear stress