Interfacial segregation and precipitates behavior in the ultrafine grained Al-based metal matrix composites
Interfacial segregation and precipitates behavior in the ultrafine grained Al-based metal matrix composites
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DOI：
10.1016/j.jallcom.2018.08.183
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发表时间：
2019-01
影响因子：
6.2
通讯作者：
Chuandong Wu;Jian Zhang;G. Luo;Q. Shen;Z. Gan;Jing Liu;Lianmeng Zhang
中科院分区：
文献类型：
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作者：
Chuandong Wu;Jian Zhang;G. Luo;Q. Shen;Z. Gan;Jing Liu;Lianmeng Zhang
为深入研究超细晶铝基复合材料的界面偏析和析出行为，以AA 7075/B 4 C复合材料为模型体系。通过低温球磨、场辅助烧结和随后的热处理合成了块体复合材料。由于Al/B 4 C界面和晶界体积分数的增加，Mg O的偏析层由15 nm左右增加到20-25 nm。透射电镜结果表明，除偏析外，晶粒内部还分布有球状GP区和片状η′相，而一些较粗的η相位于LAGB和HAGB处，取向关系为（0001）//（11（_）1）和[101（_）0] η//[110] Al。LAGB中析出相的尺寸比HAGB中的细小，这可能是由于HAGB中溶质原子的大量聚集有利于析出相的长大和粗化。
To provide insight into interfacial segregation and precipitates behavior in the ultrafine grained Al-based metal matrix composites, AA7075/B 4 C composite was selected as the model system. The bulk composite was synthesized via cryomilling, field assistant sintering and followed heat treatment. The segregation layer of MgO was observed to increase from∼ 15 nm to 20–25 nm during heat treatment due to faster solute diffusion caused by the Al/B 4 C interface and large volume fraction of grain boundaries. In addition to the segregation, representative TEM results show that the spherical GP zone and platelet η′ precipitates distribute in grain interior, while several coarser η precipitates located at LAGB and HAGB with the orientation relationship of (0001)//(1 1 (_) 1) and [10 1 (_) 0] η//[110] Al. However, the precipitates at LAGB exhibit finer size relative to those at HAGB, which could be ascribed to the higher accumulation of solute atoms at HAGB to favor the growth and coarsening of the precipitation during heat treatment.