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Indexed by:期刊论文

Date of Publication:2018-04-25

Journal:JOURNAL OF ALLOYS AND COMPOUNDS

Included Journals:SCIE、EI

Volume:742

Page Number:99-106

ISSN No.:0925-8388

Key Words:Metastable immiscible; Cu-Fe alloy; Cooling rate; Constitutional undercooling; Microstructure evolution

Abstract:Undercooling greatly influences the resultant solidification microstructure of an alloy, especially for metastable immiscible Cu-Fe alloy. In the present paper, solidification microstructure evolution of metastable immiscible Cu80Fe20 alloy was studied under different cooling conditions. For the first time, it is found that the liquid-liquid phase separation in Cu-Fe alloy is triggered by constitutional undercooling ahead of the solid-liquid interface. When the cooling rate is about 50-100 K/s, the liquid-solid transformation primarily takes place, and the liquid-liquid phase separation only exists in a small region or the interdendritic region about several tens to hundreds of microns. The liquid-liquid phase separation is ascribed to the large constitutional undercooling according to the calculation and occurs behind the liquid-solid transformation, which is different than found in previous studies. However, only normal liquid-solid transformation occurs and the morphology of the Fe-rich phase remarkably changes from cellular to developed dendrites in a cooling rate range of 350-560 K/s. The results provide significant guidance for industrial preparation and a necessary consideration for the study of metastable immiscible Cu-Fe alloy. (C) 2018 Elsevier B.V. All rights reserved.