| 7085aluminum alloy with high strength, high toughness and good corrosion resistance have been used to produce large forging for aircraft component. There is little study of the constitutive equation, microstructure evolution and influence of muti-directional forging process on the microstructure and properties of the7085aluminum alloy, which hinder the precise control of the microstructure and properties of aluminum forging. In this paper, the hot deformation behavior of the furnace-cooling7085aluminum alloy have been studied by isothermal thermal compression and the constitutive equation have been established. The evolution of deformation and solution microstructure of7085aluminum alloy were also investigated by optical microscopy and transmission electron microscope and the microstructure evolution map have been established. The effect of muti-directional forging process on recovery/recrystallization and properties has been revealed combination of muti-directional forging, finite element analysis and mechanics properties testing. The results have been shown as following:(1) The flow stress and softening behavior of furnace-cooling7085aluminum alloy were studied by isothermal compression under deformation temperature of350～450℃, the strain rate range of0.001～0.1s-1and strain of0～0.6. The results show that the flow stress increases rapidly at the deformation initial strain, and gradually softens into steady with increasing strain. The peak flow stress increases with increasing strain rate or decreasing deformation temperature. The flow stress of aluminum alloy7085during hot compression deformation can be expressed by hyperbolic sine equation including Arrhenius term. The relationship between strain and constitutive equation of parameters including activation energy, stress index and structure factor have been also analyzed and evaluated. It is showed that constitutive equation parameters decrease with increasing strain. The differences of flow stress and flow stress softening can be explained by dynamic recovery and dynamic recrystallization as well as second phase particles. (2) Effect of deformation temperature and strain rate on deformation and solution heat treatment microstructure evolution of7085A1alloy, have been investigated and the relationship among deformation condition, microstructure and properties have been established. Combination with the microstructure evolution with deformation and subsequently solution treatment, the microstructure evolution map has been established. The dominated zone of recovery have been established which was based on deformation temperature and strain rate. The results provided guideline to inhibiting recrystallization and improving comprehensive properties of the7085A1alloy(3) Combination of the constitutive equation, the recrystallization map and Deform-3D finite element analysis, the effect of muti-directional forging deformation temperature on microstructure and properties of7085aluminum alloy have been investigated. The process of muti-directional forging of7085aluminum alloy large forging piece was simulated on the platform of Deform-3D. The evolution of temperature field, effective strain field, damage field during multi-directional forging process has been analyzed. The optimal deformation temperature has been confirmed by deformation-solution recrystallization microstructure and mechanical properties. |
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