Enhancing the bake-hardening responses of a pre-aged Al-Mg-Si alloy by trace Sn additions
Enhancing the bake-hardening responses of a pre-aged Al-Mg-Si alloy by trace Sn additions
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DOI：
10.1016/j.jmst.2019.08.045
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发表时间：
2020-03
影响因子：
10.9
通讯作者：
Gang Lu;S. Nie;Jianjun Wang;Ying Zhang;Tian-hai Wu;Yu-jie Liu;Chun-ming Liu
中科院分区：
文献类型：
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作者：
Gang Lu;S. Nie;Jianjun Wang;Ying Zhang;Tian-hai Wu;Yu-jie Liu;Chun-ming Liu
通过力学试验、差示扫描量热法、电阻率法和透射电镜等研究了添加微量锡对Al-0.85Mg-0.85Si （wt%）预时效合金烘烤硬化反应的影响。结果表明，微量锡的加入抑制了预时效过程中不稳定对应物的形成，从而降低了预时效团簇的数量密度，导致溶质原子强度低、过饱和程度高。在随后的烤漆处理中，高度过饱和的溶质原子和高浓度的自由空位的存在减缓了β′′相的活化能垒，从而加速了β′′的形成。结果表明，微量锡的加入显著增强了预时效合金的烘烤硬化响应。含锡预时效Al-Mg-Si合金具有低强度和良好的烘烤硬化反应，在汽车车身蒙皮中具有广阔的应用前景。
Effects of additions of trace Sn on the bake-hardening responses of a pre-aged Al-0.85Mg-0.85Si (in wt%) alloy were investigated through mechanical tests, differential scanning calorimetry, electrical resistivity and transmission electron microscopy. Results indicate that trace Sn additions reduced the number density of pre-aging clusters by inhibiting the formation of unstable counterpart during pre-aging treatment, leading to low strength and high supersaturation of solute atoms. In a subsequent paint-bake treatment, the presence of highly supersaturated solute atoms and high concentrated free vacancies moderated the activation energy barrier of βʺ phase and thus kinetically accelerated the formation of βʺ. Consequently, the trace Sn additions enhanced the bake-hardening responses of the pre-aged alloys significantly. The Sn-containing pre-aged Al-Mg-Si alloys with low strength and great bake-hardening responses hold promising potential for automotive body skin applications.