Investigation on microstructural and microhardness evolution in as-cast and T6/heat-treated samples of a horizontally solidified AlSiCu alloy

• Published in: Journal of materials research and technology Vol. 8; no. 5; pp. 5046 - 5052
• Main Authors: Souza, Fabrício A., Costa, Marlo O., Magno, Igor A., Nascimento, Jacson M., Silva, Adrina P., Costa, Thiago S., Rocha, Otávio L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-09-2019; Elsevier
• Subjects: AlSiCu alloys; Microhardness; Microstructural evolution; T6-heat treatment; Unsteady-state horizontal solidification; Microstructural evolution; Unsteady-state horizontal solidification; T6-heat treatment; AlSiCu alloys; Microhardness
• ISSN: 2238-7854
• DOI: 10.1016/j.jmrt.2019.06.054

In this investigation, in order to evaluate the influence of microstructures on the microhardness of an aluminum-based multicomponent alloy, samples of the horizontally solidified Al-7 wt.%Si-3 wt.%Cu alloy were subjected to the T6 heat treatment. Microhardness (HV) measurements were carried out in specific zones, like in the center of the dendrites (α/Al-rich) and interdendritic regions. As expected, in as-cast samples, it has been observed high HV values in the interdendritic regions, due to the presence of the harder phases in the eutectic mixture (Si particles + Al2Cu (θ) + Fe intermetallic phases). As a highlight, hardening has been observed in both analyzed regions (α/Al-rich and interdendritic), and a similar behavior in the HV evolution, between the two investigated regions, has also been evidenced. In addition, mathematical equations have characterized the HV dependence as a function of the aging time (taging).