针对平均热膨胀系数(CTE)对航空整体结构件热变形准确预测带来较大误差这一问题，利用热机械分析仪在25~500℃范围内对7050-T7451铝合金热膨胀系数进行准确测量，采用数值拟合方法获得铝合金7050-T7451热膨胀系数随温度升高的非线性变化规律。从铝合金7050-T7451材料的合金成分和金相结构变化角度，揭示铝合金7050-T7451热膨胀系数变化的材料学内在本质；分别采用平均热膨胀系数和准确热膨胀系数模型对工件变形进行预测分析。结果表明，与平均热膨胀系数模型相比，采用准确热膨胀系数模型时热变形最大相对计算误差由17.4%降为9.5%。%Data for the coefficient of thermal expansion (CTE) of pre-stretched 7050-T7451 aluminum alloy are usually given in average values. This may bring a comparatively large error for predicting distortion of aeronautic monolithic components. To solve this problem, accurate measurements of the CTE of 7050-T7451 aluminum alloy were conducted. The measurement was carried out with the help of thermo mechanical analysis (TMA) with temperature varying from 25 to 500 ℃. Numerical fitting method was adopted to obtain the nonlinear variation rules of CTE of the alloy with temperatures. The inherent nature of CTE variation was revealed based on 7050-T7451 composition and metallography. At the end, the deformation prediction analysis of the workpiece was carried out using the average CTE and accurate CTE models, respectively. The results show that the maximum relative error obtained by the accurate CTE drops from 17.4%to 9.5%compared with that of the average CTE.
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