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Indexed by:期刊论文

Date of Publication:2014-06-01

Journal:JOURNAL OF MATERIALS RESEARCH

Included Journals:EI、SCIE、Scopus

Volume:29

Issue:11

Page Number:1256-1263

ISSN No.:0884-2914

Abstract:A comprehensive understanding of the growth pattern of intermetallic compounds (IMCs) during solidification is critical to both the crystal-growth theory and its property optimization. In this article, growth pattern and three-dimensional (3D) morphology of primary Al6Mn IMC were investigated in directionally solidified Al-3 at.% Mn alloy at a wide range of growth rates. A transition from faceted (<60 mu m/s) to nonfaceted growth (> 100 mu m/s) was observed with increasing growth rates. Correspondingly, 3D morphologies of primary Al6Mn change from a solid polyhedron to a hollow structure, and then to a dendrite. This kind of change is associated with the competitive growths of different crystal planes determined by the crystallographic anisotropy and growth kinetics of Al6Mn. A growth model based on atomic cluster attachment is proposed to reveal the growth transition, and a growth-rate ratio between different crystal planes is used to appropriately reveal the formation mechanism of different morphologies at low rates.