The influence of Cu addition and pre-straining on the natural aging and bake hardening response of Al-Mg-Si alloys
The influence of Cu addition and pre-straining on the natural aging and bake hardening response of Al-Mg-Si alloys
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DOI：
10.1016/j.jallcom.2016.07.066
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发表时间：
2016-12-15
影响因子：
6.2
通讯作者：
Liu, Qing
中科院分区：
文献类型：
--
作者：
Ding, Lipeng;Jia, Zhihong;Liu, Qing
采用维氏显微硬度计、差示扫描量热仪（DSC）和透射电镜（TEM）等方法研究了预应变对不同Cu含量的Al-Mg-Si合金自然时效和烘烤硬化的影响。结果表明，引入预应变可以抑制低Cu和高Cu合金的自然时效，提高其烘烤硬化响应（BHR）。预应变为2%是最佳工艺。加入铜元素可提高预应变抑制自然老化和改善烤漆后的BHR的效果。预应变后Cu原子在Al基体中的扩散速度慢可能是高Cu含量合金自然时效显著抑制的主要原因。在烤漆过程中，引入的位错促进Q '相的优先沉淀，并在沉淀物内产生无序结构。因此，设计新的预应变工艺时应充分考虑Cu对合金性能的影响。(C)2016爱思唯尔B. V.保留所有权利。
The effect of pre-straining on the natural aging and bake hardening of Al-Mg-Si alloys with different additions of Cu were investigated by Vickers microhardness measurements, differential scanning calorimetry (DSC) analysis and transmission electron microscopy (TEM) characterization. It is revealed that introducing pre-straining can suppress the natural aging and increase the bake hardening response (BHR) for both low and high Cu addition alloys. A pre-strain of 2% is found to be the optimum process. Addition of Cu can increase the effect of pre-straining in suppressing the natural aging and improving the BHR after paint baking. The slow diffusion rate of Cu atoms in the Al matrix is most probably the main reason for the significant suppression of natural aging in the high content Cu alloy after pre-straining. During paint baking, the dislocations introduced promote the preferential precipitation of the Q ' phase and produce a disordered structure within the precipitates. Thus designing new pre-straining processes should fully consider the influences of Cu addition to the alloys. (C) 2016 Elsevier B.V. All rights reserved.