变壁厚镁合金异型板变形均匀性优化设计

Optimization design of deformation uniformity of magnesium special-shaped plates with variable wall thickness

通过调控成形参数及结构参数能显著提升变壁厚异型板变形均匀性,保证构件在各方向的力学性能。以异型板的两个分流孔的直径、挤压成形用坯料厚度、成形温度与成形速度为设计变量,建立基于洛伦兹曲线与基尼系数的应变、晶粒尺寸及损伤值的目标函数,并结合成形载荷,建立多目标优化模型进行变形均匀性评估。结果表明:基于层次分析法得到了各因素相对合理成形工艺参数的权重及最优成形参数。试验验证表明,板挤压件成形饱满,显微组织均匀,且力学性能各向异性明显消除。显微组织调控后合金的力学性能均匀性提升,零件整体成形的变形均匀性与显微组织多指标调控有关。

By adjusting the forming parameters and structural parameters,the deformation uniformity could be significantlyimproved and the mechanical properties of the special-shaped plate with variable wall thickness in all directions could beguaranteed. The diameter of the two shunt holes of special-shaped plate,the thickness of the extrusions billet,the formingtemperature and the forming speed were used as design variables,and the strain,grain size,and damage factor were used as theobjective functions based on Lorentz and Gini coefficient. Combined with the forming load,a multi-objective optimization modelwas established to evaluate the deformation uniformity. The results show that based on the analytic hierarchy process,relativereasonable forming process parameters weight of the various factors are obtained,and the optimal forming parameters areobtained. The test verification shows that the extrusion parts are formed fully. The microstructure is uniform and the anisotropy ofmechanical properties is obviously eliminated. The uniformity of mechanical properties of the alloy is improved aftermicrostructure regulated. The deformation uniformity of the integral forming part is related to the multi-index regulation ofmicrostructure.