Effect of Fe-rich intermetallics on tensile behavior of Al–Cu 206 cast alloys at solid and near-solid states

Liu, K.; Cao, X.; Bolouri, A.; Chen, X.-G.

Abstract

Iron is one of the most common impurity elements in Al–Cu 206 cast alloys as it often causes the precipitation of Fe-rich intermetallic phases during solidification due to its extremely low solid solubility in aluminum. The characteristics of the Fe-rich intermetallics, such as type, morphology, size, and distribution, have significant influences on the tensile behaviors of the Al alloys. In the present work, two Al–Cu 206 cast alloys containing different types of Fe-rich intermetallics (dominated by either platelet β-Fe or Chinese script α-Fe) were cast and their tensile tests were performed at both solid (room temperature) and near-solid (2.8 vol. % liquid) states. It is found that the tensile properties in both solid and near-solid states are improved when the Fe-rich intermetallics change from platelet to Chinese script morphologies. During the solid-state tensile deformation, the failure occurs mainly along the platelet β-Fe intermetallics/Al matrix interface or within the Chinese script α-Fe particles. In the near-solid state, the alloy containing mainly Chinese script α-Fe is found to have more free flow paths for liquid feeding, leading to improved tensile properties. By contrast, the platelet β-Fe can cause the blockage of the liquid flow paths, leading to the degraded tensile properties and worsened susceptibility to hot-tearing.

• Presentation Conference Type: Conference Paper (published)
• Start Date: Feb 10, 2020
• Acceptance Date: Jan 1, 2019
• Online Publication Date: Feb 9, 2019
• Publication Date: Feb 9, 2019
• Deposit Date: Jul 27, 2020
• Publicly Available Date: Feb 9, 2020
• Pages: 85-96
• Series ISSN: 2367-1181
• Book Title: Shape Casting: 7th International Symposium Celebrating Prof. John Campbell's 80th Birthday
• ISBN: 9783030060336
• DOI: https://doi.org/10.1007/978-3-030-06034-3_8
• Keywords: Al–Cu alloy, Fe-rich intermetallics, Tensile properties, Solid and near-solid state, Hot-tearing
• Public URL: https://uwe-repository.worktribe.com/output/6414621
• Additional Information: First Online: 9 February 2019