Influence of Al2O3 particle pinning on thermal stability of nanocrystalline Fe
Influence of Al2O3 particle pinning on thermal stability of nanocrystalline Fe
复制标题
Al2O3颗粒钉扎对纳米晶Fe热稳定性的影响
DOI：
10.1016/j.jmst.2017.11.035
复制
发表时间：
2018
影响因子：
10.9
通讯作者：
Liu F.
中科院分区：
文献类型：
--
作者：
Shan G. B.;Chen Y. Z.;Gong M. M.;Dong H.;Li B.;Liu F.
第二相粒子钉扎被认为是阻碍晶界(GB)迁移的一种机制，因此被认为是在高温下稳定纳米晶(NC)材料的一种有效方法。分散小颗粒与颗粒间相互作用产生的钉扎力强烈依赖于颗粒的大小和体积分数。由于Al_2O_3等金属氧化物具有良好的结构稳定性和抗高温粗化能力，有望成为纳米材料的有效稳定剂。本文采用高能球磨法制备了由不同数量和尺寸的纳米Fe和Al_2O_3组成的纳米复合材料，并在不同温度(TANN)和不同时间(TANN)下进行了热处理。用X射线衍射仪和透射电子显微镜对球磨和退火态样品的显微组织进行了分析。结果表明，纳米Al_2O_3颗粒的加入不仅提高了纳米Fe颗粒的热稳定性，而且降低了颗粒在高温下的粗化速率，减小颗粒尺寸和/或增加颗粒的量，增强了颗粒对纳米Fe颗粒的稳定作用。
Second-phase particle pinning has been well known as a mechanism impeding grain boundary (GB) migration, and thus, is documented as an efficient approach for stabilizing nanocrystalline (NC) materials at elevated temperatures. The pinning force exerted by interaction between small dispersed particles and GBs strongly depends on size and volume fraction of the particles. Since metallic oxides, e.g. Al2O3, exhibit great structural stability and high resistance against coarsening at high temperatures, they are expected as effective stabilizers for NC materials. In this work, NC composites consisting of NC Fe and Al2O3nanoparticles with different amounts and sizes were prepared by high energy ball milling and annealed at various temperatures (Tann) for different time periods (tann). Microstructures of the ball milled and annealed samples were examined by X-ray diffraction and transmission electron microscopy. The results show that the addition of Al2O3nanoparticles not only enhances the thermal stability of NC Fe grains but also reduces their coarsening rate at elevated temperatures, and reducing the particle size and/or increasing its amount enhance the stabilizing effect of the Al2O3particles on the NC Fe grains.