本文選題：7050鋁合金 + 線(xiàn)膨脹系數(shù)　； 參考：《青島理工大學(xué)》2015年碩士論文

【摘要】：隨著鋁合金材料的研發(fā)與使用,鋁合金的優(yōu)異性能逐漸顯現(xiàn)了出來(lái),使得各種鋁合金被越來(lái)越廣泛地使用于眾多領(lǐng)域。近幾年隨著高鐵行業(yè)的快速發(fā)展,節(jié)能降耗意識(shí)在全球制造業(yè)的提高,對(duì)高速動(dòng)車(chē)性能要求的不斷提高,大量采用高強(qiáng)度鋁合金結(jié)構(gòu)件成為一種趨勢(shì),鋁合金結(jié)構(gòu)件可以大大減輕高速動(dòng)車(chē)的重量,減少燃料的使用提高動(dòng)車(chē)的機(jī)動(dòng)性,同時(shí),使得攜帶負(fù)載的能力大大提高,有效的緩解了安全、環(huán)保、能源[29]這三大課題,高速動(dòng)車(chē)中零部件材質(zhì)逐漸采用高強(qiáng)度鋁合金替換原來(lái)的各種鋼材。然而由于鋁合金材料具有較大的熱膨脹系數(shù),導(dǎo)致其在加工與使用過(guò)程中的尺寸穩(wěn)定性受溫度變化的影響較大,進(jìn)而導(dǎo)致了鋁合金零部件經(jīng)濟(jì)性的降低。本研究主要從理論分析與實(shí)驗(yàn)分析兩個(gè)角度出發(fā)對(duì)鋁合金的尺寸熱穩(wěn)定性進(jìn)行較為深入的研究,希望研究結(jié)論可為正確制定鋁合金的加工工藝,特別是鋁合金零部件熱變形的補(bǔ)償,提供基礎(chǔ)的理論性指導(dǎo),同時(shí)可為建立精密工程中常用材料的精確熱膨脹系數(shù)參考標(biāo)準(zhǔn)提供一定的參考依據(jù)[30]。通過(guò)對(duì)材料熱膨脹物理性以及材料熱膨脹現(xiàn)象與其比熱容(特別是晶格振動(dòng)比熱容)的關(guān)系等的研究分析,發(fā)現(xiàn)了7050-T74鋁合金的線(xiàn)膨脹系數(shù)與溫度變化之間的相關(guān)性[31]。通過(guò)鋁合金軸箱體熱變形實(shí)驗(yàn),初步得到了7050-T74鋁合金在18℃-34℃溫度范圍內(nèi)孔徑尺寸變化量與溫度之間的關(guān)系及其在該溫度范圍內(nèi)的平均線(xiàn)膨脹系數(shù)[32]。通過(guò)利用DSC實(shí)驗(yàn)儀器及相關(guān)軟件進(jìn)行鋁合金比熱容隨溫度變化測(cè)量實(shí)驗(yàn),探究了7050鋁合金尺寸熱穩(wěn)定性與其比熱容變化的相關(guān)性,并根據(jù)實(shí)驗(yàn)得出的7050-T74鋁合金熱容隨溫度變化的變化規(guī)律,通過(guò)格留乃申公式得出了線(xiàn)膨脹系數(shù)隨溫度變化的近似數(shù)學(xué)表達(dá)式以及7050-T74鋁合金在20℃~100℃(293K~373K)溫度范圍內(nèi)材料線(xiàn)膨脹系數(shù)的平均值。通過(guò)鋁合金金相組織隨溫度變化觀(guān)察實(shí)驗(yàn),探究了溫度變化時(shí)7050-T74鋁合金組織變化對(duì)鋁合金尺寸熱穩(wěn)定性的影響。通過(guò)ABAQUS對(duì)750鋁合金軸箱體建立有限元模型,并劃定網(wǎng)格類(lèi)型;對(duì)有限元模型施加相應(yīng)的邊界條件和約束,包括參數(shù)化載荷;分析軟件將根據(jù)零件幾何模型對(duì)相應(yīng)的有限元模型進(jìn)行解算,并對(duì)解算結(jié)果作相應(yīng)的后處理[33]。
[Abstract]:With the development and application of aluminum alloy materials, the excellent properties of aluminum alloy gradually appear, making various aluminum alloys are more and more widely used in many fields. In recent years, with the rapid development of high-speed rail industry, the awareness of energy saving and consumption reduction has been improved in the global manufacturing industry, and the performance requirements of high-speed motor cars have been continuously improved. It has become a trend to adopt a large number of aluminum alloy structures with high strength. Aluminum alloy structure can greatly reduce the weight of high-speed motor cars, reduce the use of fuel to improve the mobility of motor vehicles, at the same time, make the carrying capacity of load greatly improved, effectively alleviate the safety, environmental protection, energy [29] three major topics, High-strength aluminum alloy is gradually used to replace all kinds of steel in high-speed motor car. However, due to the large thermal expansion coefficient of aluminum alloy materials, the dimensional stability of aluminum alloy materials in the process of processing and use is greatly affected by the temperature change, which leads to the reduction of the economy of aluminum alloy parts. In this study, the dimension thermal stability of aluminum alloy was studied from two aspects of theoretical analysis and experimental analysis, and the conclusion of the study could be used to correctly formulate the processing technology of aluminum alloy. In particular, the compensation of thermal deformation of aluminum alloy parts provides basic theoretical guidance, and can also provide a certain reference basis for the establishment of reference standard for accurate thermal expansion coefficient of materials commonly used in precision engineering [30]. By analyzing the physical properties of material thermal expansion and the relationship between material thermal expansion phenomenon and its specific heat capacity (especially lattice vibration specific heat capacity), the correlation between linear expansion coefficient and temperature change of 7050-T74 aluminum alloy has been found [31]. The relationship between the change of pore size and temperature and the average linear expansion coefficient of 7050-T74 aluminum alloy in the temperature range of 18 鈩，

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