Abstract:
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An Al/Stainless Steel/Al lamellar composite was produced by roll bonding of the starting sheets at
400 °C. Afterward, the roll bonded sheet was cut in half and the accumulative roll bonding (ARB)
process at room temperature was applied seven times. As a result, the central steel layer fractured
and distributed in the Al matrix among different layers introduced by the repetition of roll bonding
process. The tensile results showed that the roll bonded sheet has much higher strength and strength
to weight ratio compared with the initial aluminum sheet as a result of the presence of continuous steel
core. However, poor ductility properties were observed during tensile test, which were ascribed to the
increasing deformation resistance and localized thinning of the central stainless steel sheet during the roll
bonding process. The ARBed sample exhibited lower strength compared with the roll bonded sheet due to
the breakup of stainless steel layer into many small segments. Anyway, an ultrafine grained microstructure
with average grain size of 400 nm in the aluminum matrix and 71% strain-induced martensite in the steel
segments were detected by the electron backscattered diffraction (EBSD) technique, which were found to
be responsible for the enhancement of mechanical properties compared with the initial aluminum sheet. |