Plastic Deformation Behavior and Microstructural Evolution of Al-Core/Cu-Sheath Composites in Multi-pass Caliber Rolling

Plastic deformation behavior and microstructural evolution of an Al-core/Cu-sheath composite during multi-pass caliber rolling are investigated using the finite element simulations and experimental analyses. The simulated equivalent plastic strains generated by 1 to 7 pass caliber rolling are correlated with the hardness values and microstructures measured in the longitudinal cross sections of the specimens. The average strains developed in the Al-core and Cu-sheath are almost identical, which satisfy the quasi-isostrain condition in composites with inner soft and outer hard materials. Both the Al-core and Cu-sheath exhibit increasing hardness, but decreasing hardening rates with an increase in the number of passes. The increasing hardness with an increase in the number of caliber rolling passes is attributable to the combined effect of increased dislocation density and decreased grain size. The simulated results for the hardness were shown to be in good agreement with the experimental data for Cu and Al. It was concluded that the finite element method is well placed as a tool for describing and predicting deformation behaviors during caliber rolling.