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论文类型：期刊论文

发表时间：2015-02-15

发表刊物：JOURNAL OF ALLOYS AND COMPOUNDS

收录刊物：SCIE、Scopus

卷号：622

页面范围：831-836

ISSN号：0925-8388

关键字：Metal matrix composites (MMCs); Synchrotron radiation; Microstructure; Clusters

摘要：Agglomeration of reinforcing particles has a number of deleterious effects on the properties of in situ metal matrix composites (MMCs). In order to better understand this phenomenon, the agglomerating behavior of TiB2 particles in aluminum based in situ MMCs was investigated using synchrotron radiation X-ray computed tomography (SR-CT) and field emission scanning electron microscope (FESEM). SR-CT was shown to be a powerful tool for visualizing and quantifying the three-dimensional (3D) features within the composites. Based on the SR-CT and FESEM results, a formation mechanism of the flaky agglomerates, flocculent agglomerates and clusters of coarse TiB2 particles, which are most frequently presented in the in situ Al/TiB2 composite, has been proposed. The mechanism shows that the formation of these three kinds of agglomerates can be attributed to three parallel processes, i.e. diffusing titanium atoms reacting with AlB2, aluminum melt directly reacting with emulsified salt, diffusing boron atoms reacting with TiAl3, respectively. Moreover, the mechanism may shed some light on how to design better processing techniques for obtaining homogenous particle distribution in in situ Al/TiB2 composites in the future. (C) 2014 Elsevier B.V. All rights reserved.