Stress-Strain and Structural Evolution on the Localized Interface of Stainless Steel Clad Plate

By applying different heat treatment processes (furnace cooling, air cooling, and water cooling), the stress-strain behavior of the localized interfacial region in weathering steel-stainless steel clad plates was investigated using nanoindentation, along with an analysis of interfacial microstructure formation and strengthening mechanisms. The results show that samples in the as-rolled (R), furnace-cooled (FC), air-cooled (AC), and water-cooled (WC) conditions exhibit distinct interfacial morphologies and local mechanical properties. A well-defined interfacial layer forms between the base and cladding materials, where a high density of dislocations, grain boundaries, precipitates, and nanoscale oxides significantly enhances interfacial strength, resulting in a yield strength (R_p0.2) much higher than that of either adjacent metal. Across the transition from weathering steel to stainless steel, the interfacial region consists of ferrite-interfacial layer-"new austenite"-stainless steel austenite. Its formation is predominantly governed by element diffusion, which is strongly influenced by the applied heat treatment. Variations in diffusion behavior significantly affect the microstructural evolution of the dual-phase transition zone at the interface, thereby altering the local mechanical response.