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Indexed by:期刊论文

Date of Publication:2016-09-01

Journal:CHINA FOUNDRY

Included Journals:SCIE、ISTIC

Volume:13

Issue:5

Page Number:316-321

ISSN No.:1672-6421

Key Words:ultrasonic treatment; Al-Si alloy; iron-containing intermetallics; modification

Abstract:Iron is generally regarded as an unavoidable impurity in Al-Si casting alloys. The acicular Al3Fe and beta-Al5FeSi (or Al9Si2Fe2) are common iron-containing intermetallic compounds (IMCs) in conventional structure which have a detrimental impact on the mechanical properties. In this paper, ultrasonic field (USF) was applied to modify acicular iron phases in Al-12% Si-2% Fe and Al-2% Fe alloys. The results show that the USF applied to Al-Fe alloys caused the morphological transformation of both primary and eutectic Al3Fe from acicular to blocky and granular without changes in their composition. In the case of Al-Si-Fe alloys, ultrasonic treatment led to both morphological and compositional conversion of the ternary iron IMCs. When the USF was applied, the acicular beta-Al9Si2Fe2 was substituted by star-like beta-Al12Si2Fe3. The modification rate of both binary and ternary iron IMCs relates to the USF treatment duration. The undercooling induced by the ultrasonic vibration contributes to the nucleation of intermetallics and can explain the transformation effect.