(1. 山東大學(xué) 機(jī)械工程學(xué)院 高效潔凈機(jī)械制造教育部重點(diǎn)實(shí)驗(yàn)室，濟(jì)南 250061；
2. 中航工業(yè)集團(tuán)成都飛機(jī)制造有限責(zé)任公司，成都 610092)
摘 要: 針對(duì)平均熱膨脹系數(shù)(CTE)對(duì)航空整體結(jié)構(gòu)件熱變形準(zhǔn)確預(yù)測(cè)帶來(lái)較大誤差這一問(wèn)題，利用熱機(jī)械分析儀在25~500 ℃范圍內(nèi)對(duì)7050-T7451鋁合金熱膨脹系數(shù)進(jìn)行準(zhǔn)確測(cè)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(jié)構(gòu)變化角度，揭示鋁合金7050-T7451熱膨脹系數(shù)變化的材料學(xué)內(nèi)在本質(zhì)；分別采用平均熱膨脹系數(shù)和準(zhǔn)確熱膨脹系數(shù)模型對(duì)工件變形進(jìn)行預(yù)測(cè)分析。結(jié)果表明，與平均熱膨脹系數(shù)模型相比，采用準(zhǔn)確熱膨脹系數(shù)模型時(shí)熱變形最大相對(duì)計(jì)算誤差由17.4%降為9.5%。
關(guān)鍵字: 7050-T7451鋁合金；熱膨脹系數(shù)；微觀結(jié)構(gòu)；熱處理；模型誤差
（1. Key Laboratory of High Efficiency and Clean Mechanical Manufacture, Ministry of Education,
School of Mechanical Engineering, Shandong University, Ji’nan 250061, China;
2. CAC Chengdu Aircraft Industrial (Group) Co., Ltd., Chengdu 610092, China）
Abstract: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.
Key words: 7050-T7451 aluminum alloy; thermal expansion coefficient; microstructure; heat treatment; model error
