Hot tearing of aluminum-copper B206 alloys with iron and silicon additions

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:527

Article

Kamga, H. Kamguo^1,2  Larouche, D.¹  Bournane, M.²  Rahem, A.³ 

[1] Univ Laval, Dept Min Met & Mat Engn, Aluminum Res Ctr REGAL, Saguenay, PQ G1V 0A6, Canada

[2] Univ Quebec Chicoutimi, Univ Res Ctr Aluminum CURAL, Saguenay, PQ G7H 2B1, Canada

[3] Natl Res Council Canada, ATC, Saguenay, PQ G7H 8C3, Canada

关键词: B206;    Hot tearing;    Intermetallics;    Grain refining;    Solidification;   

DOI  :  10.1016/j.msea.2010.08.025

来源: Elsevier

【 摘 要 】

Hot tearing of B206 aluminum alloys with additions of iron and silicon was studied with constrained mould casting (CRC) to investigate the combined effect of these additions on hot tear resistance. Susceptibility to hot tearing was found to increase gradually with iron content when the conditions were favorable to the formation of the beta(FeCu) phase. Additions of silicon with a Fe/Si mass ratio <= 1 and high cooling rates, which together promote the alpha(MnFe) phase at the expense of the beta(FeCu) phase, were found beneficial to the hot tearing resistance. Hot tearing sensitivity (HTS) of the alloys was evaluated with a new index defined to reflect the compliance of the torn specimens. This index showed a very good correlation with the Katgerman's hot tearing index (HCS), providing that one defines the temperature where inadequate feeding starts to be the temperature where 2% of the interdendritic volume is occupied by intermetallic phases. Examinations of the tear surfaces and profiles revealed that a premature crack opening created by insufficient healing correlates well the explanations based on the theoretical hot tearing index. The deleterious effect of iron on hot tearing was demonstrated on alloys having a coarse grain microstructure having Ti contents below or equal to 0.01 wt%. Above this limit, fine grain microstructures were obtained and the influence of iron was not strong enough to have a significant impact on the castings produced. (C) 2010 Elsevier B.V. All rights reserved.

【 授权许可】

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