On Evolution of Grain Refinement and Mechanical Properties in Cu/Low-Carbon Steel/Cu Composites Manufactured by Different Rolling Routes

The processing of Cu/low-carbon steel/Cu multilayered composites by accumulative double-pass rolling (ADPR) has been studied, and the effect of different rolling directions, including unidirectional, cross, and reverse routes, on the microstructure and mechanical properties has been analyzed. The incorporation of four cycles of the ADPR method resulted in a uniform distribution of low-carbon steel in the Cu matrix. More plastic instabilities appeared by using a unidirectional rolling route, while the fewest instabilities occurred during the cross-rolling route. This shows the enhanced deformability of layers by 90° rotation of the rolling direction. This was also confirmed by a finer ultrafine-grained microstructure and improved tensile and hardness properties. The processed samples by the cross-rolling route demonstrated higher hardness, strengths, and elongation. The highest tensile strength of 663 MPa and highest hardness of 231 HV on the Cu layer and 263 HV on the steel layer were obtained. Moreover, the variations of measured hardness from surface to center of composites were analyzed and showed the maximum value near the surface of the composites.