Thermal Stability and Mechanical Properties of Al-Zn and Al-Bi-Zn Alloys Deformed by ECAP
Thermal Stability and Mechanical Properties of Al-Zn and Al-Bi-Zn Alloys Deformed by ECAP
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DOI：
10.3390/met11122043
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发表时间：
2021-12
期刊：
影响因子：
2.9
通讯作者：
Hailong Jia;Yinan Piao;K. Zhu;Chaolu Yin;Wen-long Zhou;Feng Li;M. Zha
中科院分区：
文献类型：
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作者：
Hailong Jia;Yinan Piao;K. Zhu;Chaolu Yin;Wen-long Zhou;Feng Li;M. Zha
众所周知，超细晶和纳米晶材料具有增强的强度，但它们对热诱导的晶粒粗化很敏感。本工作旨在通过动态析出来提高等通道转角挤压(ECAP)制备的超细铝晶的热稳定性。用电子背散射衍射(EBSD)和透射电子显微镜(TEM)进行了详细的表征，揭示了ECAP和ECAP后退火过程中的组织演变。经5道次ECAP处理后，Al-8Zn和Al-6Bi-8Zn合金均呈现出超细晶结构，并沿晶界动态析出纳米级的锌颗粒。与Al-8Bi合金相比，Al-8Zn和Al-6Bi-8Zn合金中的超细晶在200℃时表现出显著的热稳定性，这主要是由于晶界上存在纳米级的锌析出物。研究结果表明，纳米级锌颗粒对超细晶的保护具有积极的作用，这对于设计热稳定性更好的超细晶铝合金具有一定的参考价值。
It is well known that ultrafine grained and nanocrystalline materials show enhanced strength, while they are susceptible to thermally induced grain coarsening. The present work aims to enhance the thermal stability of ultrafine Al grains produced by equal channel angular pressing (ECAP) via dynamically precipitation. Detailed characterization by electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) has been carried out to reveal the microstructural evolution during both ECAP and post-ECAP annealing. After five passes of ECAP, both Al-8Zn and Al-6Bi-8Zn alloys show an ultrafine grain structure together with dynamic precipitated nanoscale Zn particles along grain boundaries. Upon annealing at 200 °C, ultrafine grains in the Al-8Zn and Al-6Bi-8Zn alloys show a remarkable thermal stability compared to the Al-8Bi alloy, which is mainly due to the presence of nanoscale Zn precipitates along grain boundaries. The present work reveals that nanoscale Zn particles have a positive effect on preserving the ultrafine grains during annealing, which is useful for the design of UFG Al alloys with improved thermal stability.