Hot deformation behavior of Cu/Al laminated composites under interface constraint effect

Abstract

In order to understand the hot deformation behavior of novel Cu/Al laminated composites and evaluate the effect of interface on deformation, isothermal compression tests were conducted on the Cu/Al composites with and without a bonding interface and monometallic Al. Results show that after hot compression, there is a obvious relative sliding between Cu and Al layers of the Cu/Al composites without a bonding interface. As for the Cu/Al composites with a bonding interface, soft Al layer trends to flow synchronously with hard Cu layer under the interface constraint effect. And further microstructure examinations indicate the cooperative deformation capability of Cu/Al composites increases with increasing stain rate and decreasing deformation temperature. Strain hardening exponent, calculated based on the true stress-true strain data, also proves the effect of deformation temperature and strain rate on the cooperative deformation behavior. Meanwhile, because softening mechanism of Al layer plays a dominant role at high deformation temperature, the interface constraint effect was weaken and the flow stress of Cu/Al composites was similar to that of monometallic Al. Due to the unique composites structure, the dynamic softening mechanism of Al layer in Cu/Al composites is dynamic recrystallization during isothermal deformation. Additionally, the deformation activation energy of Cu/Al composites was calculated to be 186.43 KJ mol−1.