Experimental investigation of spring-back phenomenon through an L-die bending process for multilayered sheets produced by the accumulative press bonding technique

Abstract

For the first time in this study, the accumulative press bonding method was used to fabricate layer composites, including ceramic powder and metallic layers, and the spring-back as a functional plasticity test experimentally investigated. Al/Cu and Al/Cu/Al2O3 composites were successfully manufactured in five accumulative press bonding cycles, and in addition to spring-back evaluation, mechanical properties and plastic instability were investigated. The results showed that by the end of the third cycle, both composites were fully layered structure. However, in the fifth cycle in the Al/Cu/Al2O3 composite, plastic instability intensified and necking and fracture at all Cu layers observed due to the presence of particles in the interface and further differences in mechanical properties. As the number of accumulative press bonding cycles increases, the number of Al/Cu interfaces, which are the places where the reinforcement particles are dispersed, increases, thereby significantly improving the particle distribution and mechanical properties. The mechanical properties were improved by increasing the applied strain to the two composites, mainly due to the mechanisms underlying the severe plastic deformation processes, including cold working and microstructure improvement. The mechanical properties of the composite containing reinforcing particles improved the tensile strength and microhardness of both layers in all accumulative press bonding cycles, although the amount of elongation decreased slightly. The maximum tensile strength values of the two composites were obtained at the end of the fifth cycle, which improved the tensile strength for Al/Cu and Al/Cu/Al2O3 by about 2.65 and 2.42 times higher than unprocessed Al matrix, respectively. Experimental results of the spring-back evaluation showed that the composite with reinforcement powder due to the higher Young’s modulus had lower spring-back value. The amount of spring-back in both composites decreased with almost the same rate as the applied strain increased.