Microstructure and Mechanical Response of Steel/Ti Composites Processed by Severe Wire Drawing

Abstract The studied material was produced by integrating two structurally distinct components: microalloyed steel (BCC) as a potential matrix and commercially pure titanium (HCP) as the reinforcing layer. The primary objective of this study was to develop a heterogeneous system in which the accumulation of intense plastic deformation achieved through calibration rolling and multi-stage drawing of multilayer wire would both significantly refine the matrix microstructure and lead to the fragmentation of the reinforcing material. A thorough analysis, supported by numerical simulations, was conducted to correlate changes in the mechanical state with the heterogeneity of microstructure evolution and mechanical properties. It was revealed that complex interactions among various strengthening mechanisms influence the rheology of the examined multilayered systems. The main factors affecting the observed microstructural phenomena include the type of crystal lattice, grain boundary misorientation, multilayer system construction, and work-hardening history. It was found that, due to the high complexity of strengthening mechanisms in microalloyed steel, which promote strain accumulation, this material is a suitable choice for the matrix in heterogeneous systems. It was also observed that the possible fragmentation of the reinforcement layer, especially at the steel–titanium interface, could serve as an additional source of strengthening by increasing the contact area between the two materials, which in turn enhances the pileup effect. Furthermore, it was demonstrated that a high boundary density is essential for maximizing back stress, which serves as a microstructural mechanism enhancing the mechanical response of the investigated steel–Ti systems.