Numerical and experimental investigation on thermo-mechanical behavior during transient extrusion process of high-strength 7 × × × aluminum alloy profile

Abstract

Aluminum profile extrusion involves complex thermal, tribological, and mechanical interactions; thus, material flow and thermal behavior during extrusion process are very complicated. In this work, the material flow and thermal behavior of a 7 × × × aluminum alloy profile during an entire extrusion cycle are investigated numerically and experimentally. Hot compression tests are firstly carried out, and inverse analysis method is used to identify the material parameters of AA7N01 in Arrhenius constitutive model. The calculated global error is only 6.2 % between the predicted and experimental force–displacement curves, which verifies that the proposed model and obtained material parameters can describe well the rheological behavior of this alloy at elevated temperatures. Then a thermo-mechanical finite element model based on DEFROM-3D is built, and the transient extrusion process of the profile is simulated. By numerically analyzing the nose-end shape of the extruded profile, the evolution curves of exit temperature and of extrusion load, material flow and thermal behavior during extrusion process are investigated, respectively. Practical extrusion experiments verify the numerical model and results. Additional microstructure examination with electron backscatter diffraction (EBSD) technique also shows fine grains with the uniform grain size of about 9 μm on different locations of the extruded profile. Therefore, the material constitutive model and numerical model of extrusion process built in this work are capable enough to provide theoretical guidance in optimizing process parameters and designing extrusion dies.