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论文类型：期刊论文

发表时间：2017-09-01

发表刊物：METALS AND MATERIALS INTERNATIONAL

收录刊物：Scopus、SCIE

卷号：23

期号：5

页面范围：994-1001

ISSN号：1598-9623

关键字：alloys; self-propagating synthesis; microstructure; scanning electron microscopy (SEM); grain refinement

摘要：Al-5Ti-0.2C, Al-0.8Ti-0.2C, Al-8Ti-2C, and Al-10Ti master alloys were prepared and used to investigate the influence of excess Ti on the growth of TiC particles and its ability to nucleate Al-grains. The results of a microstructure analysis of TiC-containing alloys and refined CPAl were interrelated to the results of a refinement test. It was found that the presence of excess Ti is essential at the stage of master alloy preparation, as it facilitates the growth and uniform distribution of TiC within the structure. In Al-5Ti-0.2C alloy containing excess Ti, carbide particles grow faster and to a higher extent (from 0.29 mu m to 0.44 mu m) compared to Al-0.8Ti-0.2C alloy produced without excess Ti (from 0.29 mu m to 0.32 mu m). The results support the "Ti-transition zone theory" as the mechanism of grain refinement by TiC-containing master alloys. The refinement performance of Al-5Ti-0.2C is superior compared to the one achieved by adding Al-8Ti-2C and Al-10Ti master alloys in corresponding concentrations. For the TiC particles to become favourable nucleating sites, they must undergo certain interaction with excess Ti at the stage of master alloy preparation.