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7050-T7451鋁合金預拉伸板材熱膨脹系數(shù)變化規(guī)律及機理
發(fā)布人：上海艾荔艾金屬材料有限公司www.jshcn.cn
更新時間：2015-08-26
針對平均熱膨脹系數(shù)(CTE)對航空整體結構件熱變形準確預測帶來較大誤差這一問題，利用熱機械分析儀在25~500 ℃范圍內(nèi)對7050-T7451鋁合金熱膨脹系數(shù)進行準確測量，采用數(shù)值擬合方法獲得鋁合金7050-T7451熱膨脹系數(shù)隨溫度升高的非線性變化規(guī)律。從鋁合金7050-T7451材料的合金成分和金相結構變化角度，揭示鋁合金7050-T7451熱膨脹系數(shù)變化的材料學內(nèi)在本質(zhì)；分別采用平均熱膨脹系數(shù)和準確熱膨脹系數(shù)模型對工件變形進行預測分析。
7050-T7451鋁合金預拉伸板材熱膨脹系數(shù)變化規(guī)律及機理Varying rules and mechanism of thermal expansion coefficient
for pre-stretched 7050-T7451 aluminum alloy plate
針對平均熱膨脹系數(shù)(CTE)對航空整體結構件熱變形準確預測帶來較大誤差這一問題，利用熱機械分析儀在25~500
℃范圍內(nèi)對7050-T7451鋁合金熱膨脹系數(shù)進行準確測量，采用數(shù)值擬合方法獲得鋁合金7050-T7451熱膨脹系數(shù)隨溫度升高的非線性變化規(guī)律。從鋁合金7050-T7451材料的合金成分和金相結構變化角度，揭示鋁合金7050-T7451熱膨脹系數(shù)變化的材料學內(nèi)在本質(zhì)；分別采用平均熱膨脹系數(shù)和準確熱膨脹系數(shù)模型對工件變形進行預測分析。結果表明，與平均熱膨脹系數(shù)模型相比，采用準確熱膨脹系數(shù)模型時熱變形最大相對計算誤差由17.4%降為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.