The Effect of Solution Heat Treatment on Incipient Melting of Al₂Cu Intermetallic Phase in Lightweight Materials

Abstract:

The effects of solution heat treatment of Al6Si2Cu aluminum alloy on incipient melting of θ-Al₂Cu phase have been investigated. Solution heat treatments, in this study, are applied to improve of mechanical properties through a single-step solution heat treatment. The microstructure of as-cast specimen represents a typical dendrite structure having a secondary dendrite arm spacing of 37um. In addition to the Al matrix, a large amount of coarsen eutectic Si, θ-Al₂Cu intermetallic phases and Fe-rich phases are identified. As the solution temperature increases, the Vickers's hardness increases up to 510°C and thereafter hardness decreases at the temperature of 520°C and 530°C. This hardness behavior may closely related with microstructural evolution such as solubility of alloying elements up to 510°C and also melting of θ-Al₂Cu intermetallic phases over 510°C in this study. Consequentially, the optimal single-step solution heat treatment temperature should be 510°C to improve mechanical property.

• Periodical: Materials Science Forum (Volume 857)
• Pages: 256-260
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.857.256
• Online since: May 2016
• Authors: Chung Seok Kim*, Jin Woo Jo, Hak Min Lee
• Keywords: Al Alloy, Al₂Cu, Lightweight Materials, Melting, Solution

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