7 B50 Aluminum Alloy Homogenization And Thermal Simulation Research

7B50alloy belongs to high strength Al-Zn-Mg-Cu series alloys. Owing to high strength, high toughness, outstanding quenching degree and excellent processability, they has been widely applied in transportation, aerospace and other national industry. At present, civil engineers and material scientists still have a large gap to fill in on the research of7xxx aluminum alloys,and still do much work for the high temperature deformation in the alloy properties, processing and application pro files. As a result,the homogeneous treatment, the flow behavior and the corresponding microstructural evolution during hot compression deformation were studied.This could provide basis for the composition design, the formulation of hot working process as well as the heat treatment process and its industrial application.The effects of homogenization treatment on the microstructure of the7B50aluminum alloy were studied. And the homogenization process of the alloy was also optimized. The results show that severe dendritic segregation existed in the ingot and the alloy elements were unevenly distributed both inside the grains and along the grain boundaries. With increasing the homogenization temperature or prolonging the holding time, the residual phases dissolved into the matrix gradually and all elements became more homogenized. The proper homogenizing process was470℃/24h, which was consistent with the results of homogenization kinetic analysis.The flow behavior of7B50aluminum alloy was studied by thermal simulation test. And the microstructural evolution during hot compression deformation was also studied by OM, SEM and TEM, respectively. The results show that the flow stress increased with increasing the strain rate or decreasing the deforming temperature. The relationship between ln[sinh(ασ)] and In ε, ln[sinh(ασ)] andl/T satisfied linear type. The constitute equation of flow behavior can be expressed as ε=1.282×1010[sinh(0.0101σ)]49145exp(-134157/RT). With increasing the strain rate or decreasing the deformation temperature, the density of the dislocation decreased while the size of the grain as well as the volume fraction of the recrystallization increased and the main soften mechanism of the alloy transformed from dynamic recovery to dynamic recrystallization. According to the processing map analysis, The flow localization and the fracture are responsible for it. The suitable deformation condition for the alloy is400-440℃and0.01-0.001s-1.