Evaluation of mechanical properties and microstructure of Al/Al–12%Si multilayer via warm accumulative roll bonding process

In this study, accumulative roll bonding (ARB) process was used to produce Al/Al–12%Si multilayered composites at 300℃. Microstructure and mechanical properties of the composites were studied during various ARB cycles by field emission scanning electron microscope (FE-SEM), tensile test, and the Vickers microhardness test. The FE-SEM results revealed that, as the ARB cycle increases the thickness of individual Al and Al–12%Si sheets decreased. After the 5th cycle, Al–12%Si layers were necked, fractured and dispersed in the aluminum matrix. A new intermetallic phase Al 3.21 Si 0.47 was formed at the Al/Al–12%Si interface, indicating that the ARB process could result in a metallurgical bonding. It was observed that the tensile strength of composites improved by increasing the ARB passes, i.e. the tensile strength of the Al/Al–12%Si composite was measured to be about 5.52 and 2.17 times that of the primary 1050-Al and Al–12%Si sheets, respectively. Observations reveal that the failure mode in ARB-processed composites is of the shear ductile rupture type. The microhardness of the Al and Al–12%Si alloys were raised to 110 HV and 121 HV after five cycles.