Relationship Between Aluminum-Rich/Intermetallic Phases and Microhardness of a Horizontally Solidified AlSiMgFe Alloy

• Published in: Materials research (São Carlos, São Paulo, Brazil) Vol. 22; no. 1; p. 1
• Main Authors: Barbosa, Carolina Rizziolli, Lima, José Otávio Monteiro de, Machado, Gabriel Mendes Hirayama, Azevedo, Hugo André Magalhães de, Rocha, Fernando Sousa, Barros, André Santos, Rocha, Otávio Fernandes Lima da
• Format: Journal Article
• Language: English
• Published: Sao Carlos Universidade Federal do Sao Carlos, Departamento de Engenharia de Materiais 01-01-2019; ABM, ABC, ABPol; Associação Brasileira de Metalurgia e Materiais (ABM); Associação Brasileira de Cerâmica (ABC); Associação Brasileira de Polímeros (ABPol)
• Subjects: AlSiMg alloys; Aluminum base alloys; Cooling rate; Dendritic structure; Directional solidification; ENGINEERING, CHEMICAL; Intermetallic phases; Iron; Magnesium compounds; Mapping; MATERIALS SCIENCE, MULTIDISCIPLINARY; Metal silicides; METALLURGY & METALLURGICAL ENGINEERING; Microhardness; Microstructure; Optical microscopy; Silicon; Solidification; Solidification process; Thermal analysis; Thermal energy; Unsteady-state heat flow; Intermetallic phases; AlSiMg alloys; Microhardness; Unsteady-state heat flow; Solidification process
• ISSN: 1516-1439; 1980-5373; 1980-5373
• DOI: 10.1590/1980-5373-mr-2018-0365

An experimental study with an A356-AlSiMgFe alloy was developed to evaluate the microhardness performance in the microstructure resulting of an unsteady-state horizontal solidification process. The Al-7wt%Si-0.3wt%Mg-0.15wt%Fe alloy was elaborated and directionally solidified in a water-cooled horizontal solidification device. In order to experimentally determine the cooling and growth rates (VL and TR, respectively), a thermal analysis was also conducted during solidification. Microstructural characterization by optical microscopy, SEM/EDS elemental mapping and microanalysis of the punctual EDS compositions allowed to observe the presence of an Al-rich dendritic phase (Al(α)) with interdendritic phases second composed of an eutectic mixture: Al(α-eutectic) + Si + Al8Mg3FeSi6(π) + Mg2Si(θ). Furthermore, the dendritic microstructure was characterized by measuring the secondary dendritic spacings (λ2) along the horizontally solidified ingot. Higher HV values were observed within the eutectic mixture.