Parameter optimization of extrusion-Bc ECA technology and its effect on microstructure and properties of 7075 aluminum alloy

Equal-Channel Angular Pressing (ECAP) was carried out on 7075 aluminum alloy with a process route of Bc mode, thus, achieving the aims of refining crystal grains and improving alloy plasticity. To save cost and optimize the ECAP process, DEFORM finite element simulation of the ECAP extrusion process was conducted to determine the ratio of die shear Angle to extrusion. The results show that the mold optimum process parameters are 135° for the shear angle ( Φ ) and λ = 2 the extrusion ratio. The deformation and processing stability of the alloy at the same time met the requirements. From the simulation and experimental results of the ECAP sample, the grain size of 7075 aluminum alloy after Bc-ECAP was obviously refined from 17.311 to 9.310 μm, and the grain shape more round. The equiaxed property of the grain was also improved, and the tissue distribution more uniform. Even though the strength of 7075 aluminum alloy slightly decreased, its plasticity increased significantly from 9.9 to 18.6%.