Macroscopic Mechanical Response and Microstructure Evolution of 7075-T6 Aluminum Alloy in Taylor Impact Test
Macroscopic mechanical responses,microstructure evolution of 7075-T6 aluminum alloy during deformation under Taylor impact test were investigated by experiments and crystal plasticity finite element method.The microstructure of 7075-T6 aluminum alloy before the test was characterized by electron back scattering diffraction technique(EBSD).The internal state variables of dislocation density were introduced into CPFEM model by modifying the strengthening model and flow criterion,and the 7075-T6 aluminum alloy related model parameters were determined by combining the stress-strain curves of the dynamic compression test.The results show that the CPFEM model considering the dislocation density can effectively describe the macroscopic and microscopic mechanical responses of 7075-T6 aluminum alloy.Compared with that of the experimental results,the CPFEM model can reasonably predict the geometrical changes of cylinder after impact,and the relative errors of the predicted impact face radius and the remaining length of cylinder are within 10%of the experimental results.In addition,the CPFEM model predicts that the texture evolution of 7075-T6 aluminum alloy after impact is roughly the same as that after dynamic impacting,which shows that there are more R-Cube texture and Goss texture,while Cube texture and Cu texture decrease greatly.Meanwhile,the CPFEM model predicted there is necking in cylinder after impact;with the increase of velocity,the values of logarithmic strain and dislocation density of cylinder also increase,and the maximum value appears at the impact face.At the same velocity,the average dislocation density of the external surface is less than that of the axial at the impact face.
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