基于NSGA-Ⅱ的7050铝合金锻造力学性能多目标优化

Multi-objective optimization on forging mechanical property for 7050 aluminum alloy based on NSGA-II

为探究7050铝合金锻造工艺参数对其锻件力学性能的影响,基于7050铝合金的等温锻造工艺,设计了Box-Behnken响应曲面试验,建立了7050铝合金锻件的力学性能(抗拉强度和伸长率)与锻造工艺参数(锻造温度、变形率和锻造速度)之间的回归模型,并通过对回归模型进行方差分析,得到了各工艺参数对力学性能的影响顺序及他们之间的交互作用。基于MATLAB软件,应用非支配排序遗传算法NSGA-Ⅱ对7050铝合金力学性能回归模型寻求Pareto最优解集,得到最优工艺参数组合。结果表明:7050铝合金锻造工艺参数对其锻件抗拉强度的影响顺序为:锻造温度>锻造速度>变形率>(锻造温度×锻造速度)>(变形率×锻造速度);对伸长率的影响顺序为:锻造温度>变形率>(锻造温度×锻造速度)>(锻造温度×变形率)>锻造速度。Pareto最优工艺参数组合为:锻造温度为399.8℃、变形率为59.84%、锻造速度为15.03 mm·s^(-1),此时,抗拉强度为605.30 MPa、伸长率为14.78%,7050铝合金锻件的力学性能更优。

In order to explore the influence of forging process parameters on mechanical properties of 7050 aluminum alloy forgings,based on the isothermal forging process of 7050 aluminum alloy,the Box-Behnken response surface test was designed to establish a regression model between mechanical properties(tensile strength and elongation)and forging process parameters(forging temperature,deformation rate and forging speed)of 7050 aluminum alloy forgings,and through the variance analysis of regression model,the influence order of each process parameter on the mechanical properties and their interaction were obtained.Then,based on MATLAB software,the nondominated sorting genetic algorithm NSGA-II was used to find the Pareto optimal solution set for the regression model of 7050 aluminum alloy mechanical properties,and the optimal process parameter combination was obtained.The results show that the influence order of 7050 aluminum alloy forging process parameters on the tensile strength of forgings is forging temperature>forging speed>deformation rate>(forging temperature×forging speed)>(deformation rate×forging speed).The influence order on the elongation is forging temperature>deformation rate>(forging temperature×forging speed)>(forging temperature×deformation rate)>forging speed.Pareto optimal process parameter combination is the forging temperature of 399.8℃,the deformation rate of 59.84%and the forging speed of 15.03 mm·s^(-1).Then the tensile strength is 605.30 MPa,the elongation is 14.78%,and the mechanical properties of 7050 aluminum alloy forgings are better.