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论文类型：期刊论文

发表时间：2009-11-10

发表刊物：PROGRESS IN NATURAL SCIENCE-MATERIALS INTERNATIONAL

收录刊物：SCIE

卷号：19

期号：11

页面范围：1619-1624

ISSN号：1002-0071

关键字：Undercooling; Eutectic alloy; Metastable phase; Nucleation

摘要：High undercooling ( about 392 K) was achieved in the bulk eutectic Ni70.2Si29.8 alloy melt through glass. fluxing combined with cyclic superheating. It is found that the metastable phases Ni3Si2 and NiSi are obtained through slow post-solidification when undercooling exceeds 240 K. The metastable phases are confirmed by using the method of X-ray diffraction and differential scanning calorimetry (DSC). Based on the principle of the free energy minimum and the transient nucleation theory, the phase selection of melt is investigated with regard to the metastable phases formation in the bulk undercooled eutectic Ni70.2Si29.8 melts. The formation of metastable phases from undercooled Ni70.2Si29.8 melts is ascribed to competitive nucleation with the undercooling, i.e. high undercooling facilitates the preferential nucleation of metastable phases. (C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.