Effect of Semisolid and Heat Treatment Process on Microstructural Refinement of Al–7Si Alloy
Improving the engineering properties of Al–7Si cast alloys (300 series) provides an attractive alternative to automotive and aircraft engine industries. The solubility limit of silicon (Si) in Al contributes to the precipitation of flake-shaped Si particles with sharp edges, which function as a stre...
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| author | Mohamed Abdelgawad Gebril Mohd Zaidi Omar Intan Fadhlina Mohamed Norinsan Kamil Othman Dawod Mohamed Elabar Farag Ibrahim Haider Saziana Samat Osama M. Irfan |
| author_facet | Mohamed Abdelgawad Gebril Mohd Zaidi Omar Intan Fadhlina Mohamed Norinsan Kamil Othman Dawod Mohamed Elabar Farag Ibrahim Haider Saziana Samat Osama M. Irfan |
| author_sort | Mohamed Abdelgawad Gebril |
| collection | DOAJ |
| description | Improving the engineering properties of Al–7Si cast alloys (300 series) provides an attractive alternative to automotive and aircraft engine industries. The solubility limit of silicon (Si) in Al contributes to the precipitation of flake-shaped Si particles with sharp edges, which function as a stress riser and promote crack propagation during the eutectic phase while also weakening the protective layer’s durability. In this study, the impact of microstructure refinement of Al–7Si alloys by using cooling slope, thixoforming and the T6 heat treatment process on hardness and corrosion resistance behavior was investigated. Results showed that the microstructures of the as-cast alloy had a very coarse dendritic shape, whereas the dendritic transferred to the globular α-Al phase, and the Si particles were replaced into a lamellar- or acicular-like shape after the cooling slope and thixoforming process, respectively. The as-cast, cooling slope and thixoformed samples were subjected to the T6 heat treatment process, which enhanced the hardness to 79, 99 and 104 HV, respectively, due to Si particle refinement. The potentiodynamic test revealed that the corrosion rate dropped to 0.00790 and 0.00736 mmpy<sup>−1</sup> in the heat-treated cooling slope and thixoforming samples. This finding can be attributed to the substantially refined Si particles and reduced eutectic phase area due to the smaller cathodic to anodic area ratio. |
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| issn | 1996-1944 |
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| last_indexed | 2024-03-11T09:36:09Z |
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| spelling | doaj.art-0ee0d64de2294490b3d46b49ac402f302023-11-16T17:16:56ZengMDPI AGMaterials1996-19442023-01-01163108610.3390/ma16031086Effect of Semisolid and Heat Treatment Process on Microstructural Refinement of Al–7Si AlloyMohamed Abdelgawad Gebril0Mohd Zaidi Omar1Intan Fadhlina Mohamed2Norinsan Kamil Othman3Dawod Mohamed Elabar4Farag Ibrahim Haider5Saziana Samat6Osama M. Irfan7Department of Mechanical Engineering, Faculty of Engineering, University of Benghazi, Benghazi 16063, LibyaDepartment of Mechanical and Manufacturing Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, UKM, Bangi 43600, MalaysiaDepartment of Mechanical and Manufacturing Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, UKM, Bangi 43600, MalaysiaDepartment of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, UKM, Bangi 43600, MalaysiaDepartment of Mechanical Engineering, Faculty of Engineering, University of Benghazi, Benghazi 16063, LibyaDepartment of Mechanical Engineering, Faculty of Engineering, University of Benghazi, Benghazi 16063, LibyaDepartment of Mechanical and Manufacturing Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, UKM, Bangi 43600, MalaysiaDepartment of Mechanical Engineering, College of Engineering, Qassim University, Buraydah 51452, Saudi ArabiaImproving the engineering properties of Al–7Si cast alloys (300 series) provides an attractive alternative to automotive and aircraft engine industries. The solubility limit of silicon (Si) in Al contributes to the precipitation of flake-shaped Si particles with sharp edges, which function as a stress riser and promote crack propagation during the eutectic phase while also weakening the protective layer’s durability. In this study, the impact of microstructure refinement of Al–7Si alloys by using cooling slope, thixoforming and the T6 heat treatment process on hardness and corrosion resistance behavior was investigated. Results showed that the microstructures of the as-cast alloy had a very coarse dendritic shape, whereas the dendritic transferred to the globular α-Al phase, and the Si particles were replaced into a lamellar- or acicular-like shape after the cooling slope and thixoforming process, respectively. The as-cast, cooling slope and thixoformed samples were subjected to the T6 heat treatment process, which enhanced the hardness to 79, 99 and 104 HV, respectively, due to Si particle refinement. The potentiodynamic test revealed that the corrosion rate dropped to 0.00790 and 0.00736 mmpy<sup>−1</sup> in the heat-treated cooling slope and thixoforming samples. This finding can be attributed to the substantially refined Si particles and reduced eutectic phase area due to the smaller cathodic to anodic area ratio.https://www.mdpi.com/1996-1944/16/3/1086Al–Si alloycooling slopethixoformedheat treatmentcorrosion resistance |
| spellingShingle | Mohamed Abdelgawad Gebril Mohd Zaidi Omar Intan Fadhlina Mohamed Norinsan Kamil Othman Dawod Mohamed Elabar Farag Ibrahim Haider Saziana Samat Osama M. Irfan Effect of Semisolid and Heat Treatment Process on Microstructural Refinement of Al–7Si Alloy Materials Al–Si alloy cooling slope thixoformed heat treatment corrosion resistance |
| title | Effect of Semisolid and Heat Treatment Process on Microstructural Refinement of Al–7Si Alloy |
| title_full | Effect of Semisolid and Heat Treatment Process on Microstructural Refinement of Al–7Si Alloy |
| title_fullStr | Effect of Semisolid and Heat Treatment Process on Microstructural Refinement of Al–7Si Alloy |
| title_full_unstemmed | Effect of Semisolid and Heat Treatment Process on Microstructural Refinement of Al–7Si Alloy |
| title_short | Effect of Semisolid and Heat Treatment Process on Microstructural Refinement of Al–7Si Alloy |
| title_sort | effect of semisolid and heat treatment process on microstructural refinement of al 7si alloy |
| topic | Al–Si alloy cooling slope thixoformed heat treatment corrosion resistance |
| url | https://www.mdpi.com/1996-1944/16/3/1086 |
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