Hits:

Indexed by:期刊论文

Date of Publication:2017-06-01

Journal:MATERIALS CHARACTERIZATION

Included Journals:SCIE、EI、Scopus

Volume:128

Page Number:7-13

ISSN No.:1044-5803

Key Words:Al alloy; Segregation; Heterogeneous nucleation; High angle annular dark field (HAADF); Electron energy loss spectroscopy (EELS)

Abstract:High angle annular dark field scanning transmission electron microscope imaging and electron energy loss spectroscopy were used to elucidate the heterogeneous nucleation interface of AIB(2) in an Al-7Si alloy. Si particles were observed in the vicinity of a AlB2 particle, but no significant Si-B-rich layer (such as SiB6) was observed at the interface between AlB2 and Al, strongly indicating that the proposed creation of a layer of SiB6 at the interface between AIB(2) and Al may only be metastable and further transform to other stable phase (e.g. Si) during solidification. The solidification path of Al-Si-B alloy was also discussed based on the binary phase diagrams and a ternary Thermo-Calc simulation using the Scheil module in conjunction with the TCAL3 database. These results provide new insight into the heterogeneous nucleation behavior of Al on AlB2 influenced by solute Si.