细晶铝锭熔铸的3003及3004铝合金组织及力学性能研究

【作者】 李广钦；

【导师】 左秀荣；

【作者基本信息】 郑州大学 ， 凝聚态物理， 2007， 硕士

【摘要】 铝合金的晶粒细化对最终的产品性能起着决定性的作用，而钛是铝合金中最主要的晶粒细化元素，采用细晶铝锭来细化铝合金具有多方面的优势。本文主要研究了细晶铝锭熔炼的3003、3004铝合金微观组织和性能，并进一步研究了富铈混合稀土(RE)对细晶铝锭熔炼的3003铝合金微观组织的影响，以及由细晶铝锭熔炼的3003铝合金的均匀化制度，试验结果如下：(1)采用细晶铝锭、Al-5Ti-1B中间合金、Al-5Ti中间合金细化3003铝合金，均随钛含量增加，晶粒逐渐变小；钛含量相近时，Al-5Ti中间合金细化能力最弱，Al-5Ti-1B丝中间合金细化能力最强；细晶铝锭+Al-10RE，细晶铝锭+Al-10RE+Al-5B细化能力略强于细晶铝锭。(2)对于细晶铝锭熔炼的3003铝合金，随着富铈混和稀土含量的增加(0—0.3％)，析出相、二次枝晶间距发生距明显变化，在稀土含量为0.25％时，析出相球形化程度最高，二次枝晶间距达到最小。(3)在610℃下0-7h内均匀化处理细晶铝锭熔炼的3003铝合金，随着保温时间的延长，析出相更集中地分布于晶界处；析出相的平均直径、体积分数在6小时时分别达到最小值；圆形度在6小时时达到最大值。适宜均匀化制度为在610℃下6h。(4)由细晶铝锭熔铸的3003铝合金，在未均匀化时，铸态力学性能优于加Al-10Ti、Al-5Ti-1B中间合金试样；均匀化之后，其延伸率稍低于加Al-10Ti中间合金试样，但高于Al-5Ti-1B细化合金。由细晶铝锭熔铸的3003铝合金箔材的力学性能与Al-5Ti-1B细化试样的力学性能相当，优于Al-10Ti细化试样的力学性能；析出相与Al-5Ti-1B细化试样的相似，多为规则的块状。(5)由细晶铝锭熔铸的3004铝合金，在未均匀化时，其力学性能优于加Al-5Ti-1B中间合金试样，但劣于加Al-10Ti中间合金试样；在均匀化处理后，其性能和加Al-5Ti-1B中间合金试样的性能相近，但劣于加Al-10Ti中间合金试样。细晶铝锭熔铸的3004铝合金箔材的力学性能优于Al-5Ti-1B、Al-10Ti细化试样的力学性能，而且其中的析出相多为规则的块状。数量较少且分布较为均匀。而在Al-5Ti-1B、Al-10Ti细化的试样中，析出相形态没有规则，分布呈带状集中。更多还原

【Abstract】 It is the crucial for the properties of aluminum alloys that the grain refinement of the alloys, and titanium is the key refining element in the aluminum alloys. It has many advantages that Grain-refining aluminum ingot (GRAI) with low titanium content is used to refine grain of aluminum alloys. In this case, microstructures and properties of 3003 and 3004 aluminum alloys that are melted by GRAI are investigated, and 3003 aluminum alloys that are melted by GRAI with different cerium-rich mixtures of rare earth(RE) contents and homogenization of the alloys are investigated further. The results are as following:(1) The grain of the 3003 aluminum alloys that are melted by GRAI, 3003 aluminum alloys added Ti by Al-5Ti-1B and Al-5Ti master alloy gradually become smaller with the increase of Ti contents. The refinement efficiency of Al-5Ti master alloy is the worst and that of rod-shaped Al-5Ti-1B master alloy is the best when the Ti contents are the same. The refining efficiency of GRAI+Al-10RE and GRAI+Al-10RE+Al-5B is better than GRAI.(2) The precipitated phases and the second dendrite arm spacing are distinctly changed with the increase of RE from 0 to 0.3% in the 3003 aluminum alloys that are melted by GRAI. The precipitated phases have been obviously spheroidized, and the second dendrite arm spacing is the smallest when the RE contents is at 0.25%.(3) The 3003 aluminum alloys that are melted by GRAI are homogenized at 610℃for 0-7h. With the increase of holding time, the precipitated phases much more centralize on the grain boundary. The average diameter and the volume fraction of precipitated phases achieve the smallest values, and the roundness attains the biggest values when the holding time is 6h. So the best homogenization regime is 610℃for 7h.(4) The mechanical properties of as-cast 3003 aluminum alloys added Ti by GRAI are the best, especially its elongation is markedly higher than that added Ti by Al-10Ti master alloy and Al-5Ti-1B master alloy. After homogenization, the elongation of alloys added Ti by GRAI is a little lower than that added Ti by Al-10Ti master alloy, but higher than that added Ti by Al-5Ti-1B master alloy. The mechanical properties of 3003 aluminum foil that are melted by GRAI are similar to the foil added Ti by Al-5Ti-1B master alloy, but better than that added Ti by Al-10Ti master alloy. Morphologies and distribution of the precipitated phases of 3003 aluminum foil added Ti by GRAI and Al-5Ti-1B master alloy are similar, most of them are regular block.(5) The mechanical properties of as-cast 3004 alloys added Ti by GRAI are better than the alloys added Ti by Al-5Ti-1B, but worse than that added Ti by Al-10Ti in state, After homogenization, the mechanical properties of the 3004 Al alloys added Ti by GRAI is similar to the alloys added Ti by Al-5Ti-1B master alloy, but lower than that added Ti by Al-10Ti master alloy. The mechanical properties of 3004 aluminum foil that are melted by GRAI are better than the alloys added Ti by Al-5Ti-1B master alloy and Al-10Ti master alloy. The precipitated phases of 3004 foil that are melted by Ti addition of GRAI are more uniform distribution, most of them are regular block, but the morphologies of the precipitated phases are irregularity, and distribution is zonal in 3004 aluminum foil added Ti by Al-10Ti or Al-5Ti-1B master alloy.更多还原