轧制及退火工艺对汽车板用5182铝合金组织与性能的影响

发布时间：2018-01-05 13:37

  本文关键词：轧制及退火工艺对汽车板用5182铝合金组织与性能的影响　出处：《江西理工大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： 5182铝合金 流变应力 动态再结晶 加工图 显微组织 成形性能

【摘要】：汽车轻量化是降低汽车能耗、减少环境污染、促进汽车产业持续发展的最佳途径。铝合金作为重要的汽车轻量化材料,越来越受到广大科研工作者的关注。5xxx系铝合金板材因其合适的强度和良好的成形性能,用来替代汽车上车身板的钢铁材料已具有可行性,研究加工工艺与组织性能的关系对制备高性能的铝合金板材具有重要的意义。本课题选取了5xxx系铝合金中镁含量较高的5182铝合金为研究对象,通过单道次压缩试验、冷轧和退火试验,得出了5182铝合金高温流变应力方程、动态再结晶模型、加工图和最佳热变形、冷轧和退火工艺参数,并通过对比Al-Mg合金和5182铝合金组织性能进行验证,研究结果表明:(1)通过对5182铝合金热模拟单道次压缩试验,建立了5182铝合金高温流变应力本构方程,其中变形激活能Q为155.50kJ/mol,流变应力方程为:(2)建立了5182铝合金动态再结晶峰值应变、临界应变的模型:ε_c=0.72ε_p,ε_p=5.4402×10~(-5)ε~(0.1822)exp 38840 RT(3)在热变形过程中,变形条件对热变形组织影响极大,在低应变速率下,合金形成了尺寸较大的动态再结晶晶粒,随着应变速率的增大,动态再结晶的晶粒尺寸越来越细小;当变形温度的增大,合金的再结晶程度越大,发生动态再结晶越充分,晶粒尺寸增大;当应变量不断增加时,其动态再结晶晶粒明显长大。(4)作出了5182铝合金在真应变为0.2和0.4的加工图,5182铝合金在真应变为0.4时存在一个高功率耗散因子区域和较大安全加工区域,功率耗散效率因子大于41%,此加工区域应变速率0.01~1s~(-1)、变形温度400~500℃之间。对比热变形条件下的显微组织和加工图,变形温度450℃,应变速率在0.01~0.1s~(-1)时为最佳热加工条件。(5)通过对比不同冷轧工艺,得出二次冷轧比一次冷轧工艺下的强度会更高。二次冷轧时,成品冷轧总加工率越大,合金的强度越高,合金的晶粒尺寸越细小。在退火工艺时,退火温度升高,合金晶粒尺寸逐渐增大,在450℃时,晶粒发生了异常长大。在退火温度为350℃时,合金的成形性能达到最优。在相同的退火温度、退火时间0.5~8h下,随着退火时间的增加,合金的组织没有发生改变,晶粒尺寸没有长大的趋势,合金的性能基本上保持不变。得出了最佳冷轧退火工艺为:中间总冷轧加工率为33.3%,成品冷轧总加工率为75%,退火温度350℃,保温时间1~2h。(6)在最佳加工工艺下进行对比试验,在保证成形性能不降低的情况下,合金强度提高30MPa以上,达到了提高合金板材强度的最终目的。
[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，

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