1050 H12铝合金力学性能的响应曲面模型及优化预测

BBD Modeling and Optimization Prediction of Mechanical Properties of 1050 H12 Aluminum Alloy

摘要:

随着全球各国对南极、深海、太空等极端环境探索活动的增加，铝合金材料的低温服役性能日渐凸显重要，开展铝及铝合金在极端温度条件下力学行为与性能的研究具有重要意义。采用一种符合旋转性的球面设计方法—响应曲面设计（Box-Behnken design，BBD），对1050 H12铝合金拉伸试验参数（拉伸速率、试验温度、保温时间）进行了系统的研究，获取拉伸试验参数与1050 H12铝合金的抗拉强度和断后伸长率的关系，同时结合力学试验结果（抗拉强度、断后伸长率）得出最高优度值分别为复相关系数r₁²=0.999 1、r₂²=0.994 8及显著性水平 P值(Prob>F)均小于0.000 1的可靠数学模型。通过模型及方差分析可知，抗拉强度模型及断后伸长率模型的失拟项分别为0.077和0.117（均大于0.05），表明失拟性检验均为不显著，充分反映了模型试验的误差小，可用于精确分析和预测试验温度、保温时间、拉伸速率与抗拉强度、断后伸长率之间的关系。试验设计方案中3个拉伸试验参数对1050 H12铝合金抗拉强度、断后伸长率的影响从大到小的顺序为试验温度>拉伸速率>保温时间，其中1050 H12铝合金的抗拉强度、断后伸长率均对试验温度十分敏感，且均与试验温度、保温时间呈负相关关系，即在低温条件下1050 H12铝合金会出现低温增强增韧现象。通过响应曲面模型的精确预测得出，当试验温度为-30 ℃、保温时间为14 min、拉伸速率为9 mm?min^-1时，1050 H12铝合金的抗拉强度和断后伸长率会出现峰值。本研究为极端环境下应用1050 H12铝合金提供了有效的数据支撑。

Abstract:

The Box-Behnken design （BBD） test method， a spherical design method conforming to rotation， was adopted to systematically design the tensile test parameters of 1050 H12 aluminum alloy， including testing rate， testing temperature and holding time， and then obtained the relationship between tensile test parameters and tensile strength and elongation after fracture of 1050 H12 aluminum alloy ，at the same time， combined with the mechanical test results （tensile strength， percentage elongation after fracture） ， a reliable mathematical model with the highest merits of r₁²=0.999 1 and r₂²=0.994 8， and P values（Prob>F） both levels less than 0.000 1， respectively， was obtained. The model and analysis of variance， the loss of fit terms of the tensile strength model and percentage elongation after fracture model respectively are 0.077 and 0.117 （both greater than 0.05） ， and the loss of fit tests are not significant， which fully reflects the small error of the model test. So it can be used to accurately analyze and predict the relationship between the test temperature， holding time， tensile rate and tensile strength and percentage elongation after fracture. The influence degree of the three tensile process parameters on the tensile strength and percentage elongation after fracture of 1050 H12 aluminum alloy in the test design from large to small is as follows： temperature， tensile strength and holding time， and it can be seen that the tensile strength and percentage elongation after fracture of 1050 H12 aluminum alloy are extremely sensitive to the test temperature and are negatively correlated with the test temperature and holding time， that is， 1050 H12 aluminum alloy will be strengthened and toughened at low temperature. According to the accurate prediction of response surface model， when the testing temperature is -30 ℃， the holding time is 14 min， and the testing rate is 9 mm?min^-1， the tensile strength and percentage elongation after fracture of 1050 H12 aluminum alloy will peak within the range of tensile parameters in this study.