A Study Of Microstructure And Mechanical Properties Of Cu/Brass Layered Composites

Accumulative roll bonding(ARB)is increasingly used to fabricate dissimilar metallic multi-layered composites.In this study,ARB was used to fabricate composites of commercial pure copper and H68 brass.Then the composites were annealed at 250? and 500? for one hour respectively.The microstructure of the composites were characterized by optical microscope,scanning electron microscopy,X-ray diffraction and Energy Dispersive Spectrometer(EDS).Mechanical properties were investigated by micro-hardness test,tensile test and three point bending test.The effects of interface bonding strength and interface diffusion on mechanical properties of ARBed samples were investigated.The main conclusions of the present research are as follows:(1)Strength and plasticity of the samples processed by two and three ARBed cycles and subsequent annealing at 250? were improved compared with that in the as-ARB processed sample.In the sample processed by three ARB cycles,dynamic recrystallization occurred in the brass layer.(2)Brass texture appeared in the copper layer,this indicates that during rolling process brass changed the texture evolution of copper.This is because shear band in the brass penetrated the copper/brass interface and affected the deformation mode of the copper.(3)The hardness of the brass was affected by the interface bonding strength and diffusion.After one and two ARB cycles hardness values were higher near the interface than those at the other locations.After annealing at 500?,a zinc-deficient layer was formed at the interface due to diffusion of Zn,correspondingly the hardness of brass was lower near the interface than at the center.