The Hot Roll Bonding Process And Interface Diffusion Of 5A06Al/AZ31Mg Laminated Composites

As a kind of new composite material with the attractive properties,Al/Mg composite consist of aluminum alloys and magnesium alloys has a very wide application prospect.In this study,5A06 aluminum plate and AZ31 Mg plate were prepared by hot-rolled bonding process.By using of optical microscope,scanning electron microscopy(SEM),energy dispersive spectrometer(EDS)multi-function testing machine etc.the interface,the microstructure of AZ31 Mg,the bonding strength of 5A06Al/AZ31 Mg composite were studied.Meanwhile,the effects of the parameters of rolling and annealing on the mechanical and physical properties of the composite plate was also analyzed.Based on the theory of B.E.Eyrkab,diffusion kinetics equation under different hot rolling reduction rates and annealing conditions was established in order to provide some theoretical basis for control of interface diffusion layer and optimization of the rolling process parameters.The inter plate of the 5A06Al/AZ31 Mg layered composite prepared by hot rolling at 450? with the reduction ratio of 35%~50% achieves good combination with a certain thickness of diffusion layer.And the diffusion layer thickness affects the bonding strength which first increased then decreased with the increasing of rolling deformation and temperature.The max value of bonding strength,about 72.57 MPa was reached at the rolling temperature 450 ?,the rolling reduction rate of 45%.The dynamic recrystallization in the magnesium layer occurred in the hot rolling process,and the grain size of Mg layer increased with the increase of rolling temperature,first decreased then coarsened with the rolling deformation.The 5A06Al/AZ31 Mg composite plate was subject to annealing and the thickness of the diffusion layer of the composite plate increased with the increasing of annealing temperature and annealing time.However,the bonding strength increased firstly and then decreased with annealing time and the annealing temperature.The grains in magnesium layer are equiaxed and its size also increased firstly and then decreased with annealing time and the annealing temperature.By means of EDS analysis of diffusion layer annealed at high temperature or long time,it is found that the intermetallic compound near the Al alloy is Al3Mg2,which is close to the Mg alloy by Al12Mg17.The mathematical model of the growth kinetics of the diffusion layer was established by fitting the parameters of the diffusion layer thickness under different rolling conditions.