Crystallographic continuity and interface integrity in multilayer laminates from dissimilar stainless steels

The roll-bonding process is a solid-state joining technique that enables the production of multilayered metallic laminates by bonding distinct metal sheets. This process exploits atomic diffusion, facilitated by temperature and mechanical stresses applied during rolling. A key advantage of roll bonding is its ability to merge the unique properties of the base materials, yielding advanced functional and structural materials optimized for a variety of applications. In this study, we investigate, for the first time, the hot roll bonding of various stainless-steel families (specifically austenitic, ferritic, martensitic, and duplex). Microstructural and mechanical analyses reveal defect-free bonding interfaces, confirmed by the absence of porosity and secondary phases. Electron backscatter diffraction (EBSD) analysis shows grain growth across the interfaces, demonstrating excellent microstructural continuity. Elemental diffusion profiles measured via EDS revealed gradual changes in Cr, Ni, and Mo concentrations across interfaces extending over distances of approximately 50 to 100 µm, confirming effective chemical homogenization. Mechanical shear tests demonstrated interface strengths exceeding 600 MPa, with failure consistently occurring in the base material rather than at the bonded interfaces. This work underscores the potential of roll bonding as a promising approach for the development of advanced multilayered materials with gradient structures and tailored properties. Our findings lay the groundwork for further exploration of roll bonding as a versatile manufacturing method for high-performance, environmentally friendly, and cost-effective metallic components, with the added benefit of facilitating scrap reuse.