5xxx系铝合金板材的组织和织构对其成形性和锯齿屈服行为的影响
发布时间：2018-12-13 00:49
【摘要】：5xxx系铝合金具有较高的比强度和较好的成形性能,成为汽车轻量化材料的首选。合金的成形性能与塑性各向异性密切相关,而塑性各向异性从本质上又决定于晶体学织构。为了进一步提高合金的使用性能,更好的满足汽车轻量化的需求,本文在商用5182铝合金的基础上,进一步提高合金中的Mg含量,控制其它合金元素的含量,优化轧制及退火工艺,同时改善了合金的力学性能和成形性能。本文系统研究了Mg、Cu、Zn合金元素以及轧制和再结晶退火工艺对合金组织性能及织构的影响。同时针对室温变形时A1-Mg合金中的锯齿屈服效应,详细分析了合金成分、加工参数、加载应变速率等条件对锯齿屈服效应的影响,并结合动态应变时效微观机制,对上述现象进行了解释。得到了以下结论： 获得了一种高强度易成形的5xxx系铝合金,其成分如下：Al-6.1Mg-0.15Cu-0.2Mn-0.1Si-0.2Fe-0.05Cr(wt%),该合金经两次冷轧、中间退火及450℃/1h再结晶退火后,与商用5182铝合金相比,在保持合金成形性能基本不变的前提下,大幅度提高了合金的力学性能。 合金的成形性能随Mg和Cu含量的增加均呈现“∧”型变化。合金元素含量没有改变合金的织构组分,但对织构密度及其体积分数产生了较大影响。粒子激发形核作用大大降低了合金的织构密度,再结晶退火后的合金通过应变诱导晶界迁移机制保留了部分轧制织构取向,提高了合金的成形性能。随最终冷轧压下率的增加,合金的成形性能下降,较高的中间退火温度和再结晶退火温度有利于提高合金的成形性能。 合金在较宽的加载应变速率范围内都具有锯齿屈服效应。随着应变速率的减小,拉伸曲线上的锯齿越来越强烈,高Mg合金呈现从A类到B类再到C类锯齿的转变,并且出现临界应变。应力跌幅和再加载时间随应变和Mg含量的增加而增大,并且其增大的速率也随固溶Mg原子浓度的增加而增大。退火态的合金中,应力跌幅和再加载时间随晶粒尺寸的增大而减小：冷轧态的合金由于具有较高的晶界和位错密度,其锯齿屈服效应最为强烈。
[Abstract]:5xxx aluminum alloy has high specific strength and good formability, so it is the first choice of automotive lightweight materials. The formability of alloys is closely related to plastic anisotropy, which is essentially determined by crystallographic texture. In order to further improve the performance of the alloy and better meet the requirement of automobile lightweight, this paper, on the basis of commercial 5182 aluminum alloy, further increases the content of Mg in the alloy and controls the content of other alloy elements. The rolling and annealing processes were optimized and the mechanical properties and formability of the alloy were improved. The effects of elements of Mg,Cu,Zn alloy, rolling and recrystallization annealing on the microstructure and texture of the alloy have been studied systematically in this paper. Aiming at the sawtooth yield effect of A1-Mg alloy during room temperature deformation, the effects of alloy composition, processing parameters and strain rate loading on the sawtooth yield effect are analyzed in detail, and the dynamic strain aging microcosmic mechanism is combined. The above phenomena are explained. The following conclusions are obtained: a kind of 5xxx aluminum alloy with high strength and easy forming has been obtained. The composition of the alloy is as follows: Al-6.1Mg-0.15Cu-0.2Mn-0.1Si-0.2Fe-0.05Cr (wt%), which has been cold-rolled twice. After intermediate annealing and recrystallization annealing at 450 鈩，
本文编号：2375552
[Abstract]:5xxx aluminum alloy has high specific strength and good formability, so it is the first choice of automotive lightweight materials. The formability of alloys is closely related to plastic anisotropy, which is essentially determined by crystallographic texture. In order to further improve the performance of the alloy and better meet the requirement of automobile lightweight, this paper, on the basis of commercial 5182 aluminum alloy, further increases the content of Mg in the alloy and controls the content of other alloy elements. The rolling and annealing processes were optimized and the mechanical properties and formability of the alloy were improved. The effects of elements of Mg,Cu,Zn alloy, rolling and recrystallization annealing on the microstructure and texture of the alloy have been studied systematically in this paper. Aiming at the sawtooth yield effect of A1-Mg alloy during room temperature deformation, the effects of alloy composition, processing parameters and strain rate loading on the sawtooth yield effect are analyzed in detail, and the dynamic strain aging microcosmic mechanism is combined. The above phenomena are explained. The following conclusions are obtained: a kind of 5xxx aluminum alloy with high strength and easy forming has been obtained. The composition of the alloy is as follows: Al-6.1Mg-0.15Cu-0.2Mn-0.1Si-0.2Fe-0.05Cr (wt%), which has been cold-rolled twice. After intermediate annealing and recrystallization annealing at 450 鈩，
本文编号：2375552
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