Effects of Zn Addition and Aging Condition on Serrated Flow in Al-Mg Alloys
Effects of Zn Addition and Aging Condition on Serrated Flow in Al-Mg Alloys
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DOI：
10.4028/www.scientific.net/msf.794-796.483
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发表时间：
2014-06
期刊：
影响因子：
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通讯作者：
K. Matsumoto;Y. Aruga;Hidemasa Tsuneishi;H. Iwai;M. Mizuno;H. Araki
中科院分区：
文献类型：
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作者：
K. Matsumoto;Y. Aruga;Hidemasa Tsuneishi;H. Iwai;M. Mizuno;H. Araki
研究了加Zn和不加Zn的Al-Mg合金在不同时效条件下的锯齿状流动现象，重点研究了析出相的作用。对Al-6mass%Mg-0~3mass%Zn合金进行753~803K固溶处理，淬火后室温时效。部分在自然老化2.6Ms后，在323~573K下进行人工老化86.4ks。通过拉伸试验对其锯齿状流动特性进行了评价。用差示扫描量热法、透射电镜、原子探针层析成像和正电子湮灭寿命谱对其微观结构进行了表征。随着锌添加量的增加和自然时效时间的延长，锯齿状流动的发生时间有所推迟。自然时效后，在较高的温度下进行人工时效，则降低了初始应变。Al-Mg-Zn合金在自然时效过程中形成大量小的共格Zn-Mg团簇，在随后的人工时效过程中转变为较大的非共格亚稳定相。这些结果表明，干扰锯齿状流动的机制与空位捕获效应有关，空位捕获效应被相干团簇增强。
The serrated flow phenomena in Al-Mg alloys with and without Zn were investigated after aging on several conditions, focusing on the role of precipitates. Al-6mass%Mg-0~3mass%Zn alloys were solution treated at 753~803K, quenched, and then aged at room temperature. Further artificial aging at 323~573K for 86.4ks was performed for some of them after natural aging for 2.6Ms. The serrated flow behavior was evaluated by tensile test. Microstructure was characterized by differential scanning calorimetry, transmission electron microscopy, atom probe tomography, and positron annihilation lifetime spectroscopy. The increase in the amount of Zn addition and the natural aging time lead to a delayed onset of serrated flow. The artificial aging at higher temperatures after natural aging, on the other hand, decreases the onset strain. A large number of small coherent Zn-Mg clusters are formed during natural aging in the Al-Mg-Zn alloys, which are transformed to the larger incoherent meta-stable precipitates during subsequent artificial aging. These results suggest that the mechanism of interfering with serrated flow is related to the vacancy trapping effect, which is enhanced by the coherent clusters.