| Abstract Scope |
Following Archard’s law “the harder, the better”, typical blades are nowadays honed from carbide-rich martensitic stainless steel and coated to achieve high hardness and wear resistance. However, the presence of different constituents inside the material (carbides, martensite, retained austenite) produces spatial heterogeneity in mechanical properties along the sharp edge, which in turn leads to mixed mode II/III cracking and chipping of the blade. To improve these materials, we designed a new manufacturing process that uses tapered rolls to locally produce solid-solutioned ultrafine ferritic grains through plastic deformation. This process leads to a gradient-induced toughening effect and high strength near the sharp edge, sufficient to avoid cracking from compressive and bending loads. We characterized this graded material through electron backscattered diffraction and Picoindentation hardness tests. Moreover, a sharp edge produced with this material was tested in in-situ SEM cutting experiments to show the improved mechanical response with respect to commercial blades. |