Effect of room temperature storage time on precipitation in Al–Mg–Si(–Cu) alloys with different Mg/Si ratios
Effect of room temperature storage time on precipitation in Al–Mg–Si(–Cu) alloys with different Mg/Si ratios
复制标题
室温储存时间对不同 Mg/Si 比 Al-Mg-Si(-Cu) 合金析出的影响
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
R. Holmestad
中科院分区：
文献类型：
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作者：
S. Wenner;C. Marioara;S. Andersen;R. Holmestad
摘要 研究了人工时效前自然时效时间对四种 Al-Mg-Si(-Cu) 合金的影响，其中含有 0.4% Mg + 0.8% Si 和 0.8% Mg + 0.4% Si，含或不含 0.14 at.% Cu。通过透射电子显微镜对沉淀物微观结构进行定量。改变在 200°C 下老化 170 分钟之前的储存时间，我们观察到几分钟后初始硬度增加，几小时后下降，几周后再次增加。富镁无铜合金的硬度下降最为明显，这是由于沉淀物体积分数减少所致。无论合金的 Mg/Si 比例如何，添加 Cu 都会产生更精细的微观结构、更高的硬度并减少自然时效的负面影响。储存 1 周后，在含 Cu 富硅合金和富镁合金中观察到含 Cu 析出物分数 L 和 Q' 分别增加。
Abstract The effect of natural ageing time before artificial ageing has been investigated in four Al–Mg–Si(–Cu) alloys, with 0.4% Mg + 0.8% Si and 0.8% Mg + 0.4% Si, both with and without 0.14 at.% Cu. The precipitate microstructure was quantified by means of transmission electron microscopy. Varying the storage time before ageing for 170 min at 200°C, we observe an initial hardness increase after minutes, a decrease after several hours and another increase after weeks. The hardness decrease was most pronounced in the Mg-rich Cu-free alloy, caused by a reduced precipitate volume fraction. Adding Cu produces finer microstructures, higher hardness and reduces the negative effect of natural ageing regardless of the Mg/Si ratio of the alloy. With 1 week storage, an increase in the fraction of the Cu-containing precipitates L and Q′ was observed in the Cu-containing Si-rich and Mg-rich alloys respectively.