Optimization of multi-directional forging parameters of large-scale Mg-Gd-Y-Zn-Zr alloy forged part guided by finite element simulation

Abstract Based on the thermal compression stress-strain curves and three-dimensional processing maps of the homogenized Mg-8.5Gd-2.5Y-1.5Zn-0.5Zr (wt.%) alloy in our previous published work, we performed a comprehensive investigation to assess the influence of multi-directional forging parameter (i.e. per-pass reduction, pass number and temperature) on the strain uniformity of large-scale forged part by finite element simulation. The results indicate that compared to forging temperature and pass reduction, the pass number of deformation significantly influences the strain uniformity. The optimal forging parameters were obtained for a large-scale ingot with 430 mm in diameter and 440 mm in height, i.e., the forging temperature of 450°C, pass reduction of 40%, pass number of 5 and forging speed of 10 mm/s. Finally, a large-scale forged part with the diameter of 900 mm and the height of 100 mm was successfully produced under the optimal forming condition. The average grain sizes of edge and center regions of the forged part are (4.08 ± 3.25) µm and (5.58 ± 2.19) µm, respectively, exhibiting a small microstructure difference. The mechanical properties anisotropy is also low, and the tensile strength differences at each position are less than 20 MPa.