Manufacturing Al/steel multilayered composite by accumulative roll bonding and the effects of subsequent annealing on the microstructural and mechanical characteristics

In this research, multilayered Al/steel composites were produced by accumulative roll bonding (ARB) process using Al-1100 and St-12 sheets up to three cycles. Microstructure and mechanical properties of the Al/steel multilayered composite were studied during various ARB cycles by scanning electron microscopy (SEM), tensile and Vickers microhardness tests. It was observed that after the second ARB cycle, steel layers were necked and fractured and tensile properties decreased dramatically. For this reason, the effects of annealing temperature and time on the mechanical properties of composite were evaluated at the first cycle. The results indicated that generally, strength of Al/steel composite decreased and elongation increased after annealing. However, the strength between 300 °C and 400 °C is approximately constant. Additionally, the annealing treatment at 500 °C dramatically reduced the strength due to the formation of a brittle intermetallic layer with high hardness at the Al/steel interface.