發(fā)布時間：2018-01-05 13:37

  本文關鍵詞：軋制及退火工藝對汽車板用5182鋁合金組織與性能的影響　出處：《江西理工大學》2016年碩士論文　論文類型：學位論文

  更多相關文章： 5182鋁合金 流變應力 動態(tài)再結晶 加工圖 顯微組織 成形性能

【摘要】：汽車輕量化是降低汽車能耗、減少環(huán)境污染、促進汽車產(chǎn)業(yè)持續(xù)發(fā)展的最佳途徑。鋁合金作為重要的汽車輕量化材料,越來越受到廣大科研工作者的關注。5xxx系鋁合金板材因其合適的強度和良好的成形性能,用來替代汽車上車身板的鋼鐵材料已具有可行性,研究加工工藝與組織性能的關系對制備高性能的鋁合金板材具有重要的意義。本課題選取了5xxx系鋁合金中鎂含量較高的5182鋁合金為研究對象,通過單道次壓縮試驗、冷軋和退火試驗,得出了5182鋁合金高溫流變應力方程、動態(tài)再結晶模型、加工圖和最佳熱變形、冷軋和退火工藝參數(shù),并通過對比Al-Mg合金和5182鋁合金組織性能進行驗證,研究結果表明:(1)通過對5182鋁合金熱模擬單道次壓縮試驗,建立了5182鋁合金高溫流變應力本構方程,其中變形激活能Q為155.50kJ/mol,流變應力方程為:(2)建立了5182鋁合金動態(tài)再結晶峰值應變、臨界應變的模型:ε_c=0.72ε_p,ε_p=5.4402×10~(-5)ε~(0.1822)exp 38840 RT(3)在熱變形過程中,變形條件對熱變形組織影響極大,在低應變速率下,合金形成了尺寸較大的動態(tài)再結晶晶粒,隨著應變速率的增大,動態(tài)再結晶的晶粒尺寸越來越細小;當變形溫度的增大,合金的再結晶程度越大,發(fā)生動態(tài)再結晶越充分,晶粒尺寸增大;當應變量不斷增加時,其動態(tài)再結晶晶粒明顯長大。(4)作出了5182鋁合金在真應變?yōu)?.2和0.4的加工圖,5182鋁合金在真應變?yōu)?.4時存在一個高功率耗散因子區(qū)域和較大安全加工區(qū)域,功率耗散效率因子大于41%,此加工區(qū)域應變速率0.01~1s~(-1)、變形溫度400~500℃之間。對比熱變形條件下的顯微組織和加工圖,變形溫度450℃,應變速率在0.01~0.1s~(-1)時為最佳熱加工條件。(5)通過對比不同冷軋工藝,得出二次冷軋比一次冷軋工藝下的強度會更高。二次冷軋時,成品冷軋總加工率越大,合金的強度越高,合金的晶粒尺寸越細小。在退火工藝時,退火溫度升高,合金晶粒尺寸逐漸增大,在450℃時,晶粒發(fā)生了異常長大。在退火溫度為350℃時,合金的成形性能達到最優(yōu)。在相同的退火溫度、退火時間0.5~8h下,隨著退火時間的增加,合金的組織沒有發(fā)生改變,晶粒尺寸沒有長大的趨勢,合金的性能基本上保持不變。得出了最佳冷軋退火工藝為:中間總冷軋加工率為33.3%,成品冷軋總加工率為75%,退火溫度350℃,保溫時間1~2h。(6)在最佳加工工藝下進行對比試驗,在保證成形性能不降低的情況下,合金強度提高30MPa以上,達到了提高合金板材強度的最終目的。
[Abstract]:Automobile lightweight is the best way to reduce automobile energy consumption, reduce environmental pollution and promote the sustainable development of automobile industry. Aluminum alloy is an important lightweight material for automobile. More and more scientific research workers pay attention to. 5xxx aluminum alloy sheet because of its suitable strength and good formability, it is feasible to replace the steel material on the automobile body plate. It is of great significance to study the relationship between processing technology and microstructure and properties for the preparation of high performance aluminum alloy sheet. In this paper, 5182 aluminum alloy with high magnesium content in 5xxx series aluminum alloy is selected as the research object. Through single pass compression test, cold rolling and annealing test, the high temperature rheological stress equation, dynamic recrystallization model, processing diagram and optimum hot deformation, cold rolling and annealing process parameters of 5182 aluminum alloy were obtained. By comparing the microstructure and properties of Al-Mg alloy and 5182 aluminum alloy, the results show that the single pass compression test of 5182 aluminum alloy is carried out. The constitutive equation of high temperature rheological stress of 5182 aluminum alloy is established. The deformation activation energy Q is 155.50kJ / mol. The model of peak strain and critical strain of dynamic recrystallization of 5182 aluminum alloy was established. In the process of hot deformation, the deformation condition has a great influence on the microstructure of thermal deformation. At low strain rate, the dynamic recrystallization grains with larger size were formed. With the increase of strain rate, the grain size of dynamic recrystallization became smaller and smaller. When the deformation temperature increases, the recrystallization degree of the alloy increases, the dynamic recrystallization occurs more fully, and the grain size increases. When the strain is increasing, the dynamic recrystallization grain grows up obviously.) the processing diagram of 5182 aluminum alloy is made, which is 0.2 and 0.4 in real time. 5182 aluminum alloy has a high power dissipation factor region and a large safe processing area when the true value should be 0. 4, and the power dissipation efficiency factor is greater than 41%. The strain rate of this processing area is 0.01 ~ (-1) ~ (-1) and the deformation temperature is between 400 ~ 500 鈩，

本文編號：1383367