Heterogeneities in the microstructure and mechanical properties of high-Cr martensitic stainless steel produced by repetitive hot roll bonding

A multi-layered plate with robust interfacial strength composed of high-Cr martensitic stainless steel was produced via repetitive hot roll bonding (RHRB) at elevated temperature. The minimum processing temperature required for the production of multi-layered plates turned out to be in the two-phase region between the A₁ and A₃ temperatures of stainless steel. Decarburization took place on the surface layer of each process cycle and multi-layered plates were produced with a carbon content that fluctuated along the thickness direction that constitutes a composite plate. The multi-layered composite structure revealed an effective combination of strength and ductility. Also, strong bonding results at each interface were validated via tensile testing with in-situ observation from the sides of the specimens during deformation.