Al-based magnetic composites produced by accumulative roll bonding (ARB)

Accumulative roll bonding (ARB) was used to fabricate Al/Ni (with two initial Ni thicknesses) and Al/Ni/Fe3O4 composites. During ARB, Ni layers necked and fractured owing to the difference in flow properties of Al and Ni. In addition, large and elongated clusters of Fe3O4 particles were broken into smaller ones and distributed gradually in Al matrix. After the fourth and sixth cycle, weak bonding and several pores were observed at particle/matrix interface while the bonding quality increased after the eighth cycle. Results show that after eight cycles, an Al-based composite with a satisfactorily magnetic behavior was produced. The Al/Ni (0.5) composite exhibited the highest tensile strength (182 MPa) with the highest value of saturation magnetization (13.47 emu/g). The relative permeability decreased with increasing frequency for a given number of ARB cycles. The Fe3O4 particles caused the saturation magnetization to decrease and the critical frequency to increase due to the eddy current effects. (C) 2016 Elsevier B.V. All rights reserved.