Abstract
The combined deformation technology used to enhance the properties of gradient metal materials with a nanostructured surface layer has attracted significant attention due to their exceptional properties, making them highly promising for industrial applications. These materials exhibit a unique combination of high strength, ductility, and wear resistance. However, achieving the desired properties and gradient microstructure in these materials requires precise control over the deformation process. The objective of this work was to investigate the effect of combined deformation processing, integrating drawing through stationary (freely rotating) RSR mill rolls followed by die drawing, on the evolution of microstructure and the mechanical properties of initially coarse-grained alpha-brass. The laboratory experiment was conducted at a room temperature using rods with a diameter of 30 mm. The results revealed that introducing radial-shear broaching had a significant effect on the properties and microstructure of the material. The combined technological process of integrating radial-shear broaching through stationary rolls followed by die drawing, successfully produced a pronounced gradient microstructure in CuZn36 brass rods, where the grain size was refined to 1 μm in the surface zone while remaining at 20 μm at the centre. This structural refinement resulted in a symmetrical, U-shaped microhardness distribution across the cross-section, with peak values reaching 170 ± 4 HV0.1 in the heavily deformed surface layer compared to 84 ± 3 HV0.1 in the initial annealed state.