Hot deformation behavior of the AA6016 matrix composite reinforced with in situ ZrB2 and Al2O3 nanoparticles

The hot deformation tests of in situ ZrB2 and Al2O3 nanoparticles reinforced AA6016 matrix composite were studied at deformation temperature of 300 degrees C-450 degrees Cand strain rate of 0.001-1 s(-1). In this paper, the ZrB2 and Al2O3 nanoparticles were successfully prepared by direct melt reaction method firstly. Based on experimental results, the flow stress increased rapidly with the increasing true strain and decreased with the increasing temperature. Constitutive equation of the composite can be established based on the Arrhenius constitutive model. The processing map based on dynamic material model showed two stable processable domains: Domain A(300-360 degrees C/0.08-0.01 s(-1)), which was controlled by dynamic recovery and domain B(410-430 degrees C/0.37-1 s(-1)), which was typical dynamic recrystallization structure. The microstructural changes of the samples after deformed were observed through optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). It was concluded that these two kinds of reinforced particles can greatly promote recrystallization nucleation at high temperatures. Thus, domain B is optimum hot processing window.