Analysis of the Effect of Simultaneous Melt Shearing and Cooling on Grain Formation and Rheology of A356 Aluminum Alloy
Despite the dozens of earlier research verifications, the contribution of shearing of molten metallic alloys during their solidification to grain formation is still ambiguous. Also, modeling of this phenomenon has received very little attention. Experiments were conducted in this study to investigat...
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MDPI AG
2023-09-01
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| Series: | Crystals |
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| author | Mahmoud Ahmadein Naser A. Alsaleh Mahmoud Ahmed Elsayed Sabbah Ataya |
| author_facet | Mahmoud Ahmadein Naser A. Alsaleh Mahmoud Ahmed Elsayed Sabbah Ataya |
| author_sort | Mahmoud Ahmadein |
| collection | DOAJ |
| description | Despite the dozens of earlier research verifications, the contribution of shearing of molten metallic alloys during their solidification to grain formation is still ambiguous. Also, modeling of this phenomenon has received very little attention. Experiments were conducted in this study to investigate the effect of the shear rate on the density, size, and shape factor of the formed grains up to a solid fraction of 0.15 for the solidifying A356 aluminum alloy in the coaxial cylinder viscometer. The rheology of the formed semisolid slurry was studied as well. Results exhibited morphological evolution and grain refinement. The grain number density increased from 5 × 10<sup>8</sup> m<sup>−3</sup> in the absence of melt shearing to reach 4 × 10<sup>9</sup> m<sup>−3</sup> at the shear rate of 250 s<sup>−1</sup>. Also, the shape factor was improved to reach 0.78. Based on the experimental investigations, the grain number density under shearing was correlated to the shear rate and the grain number density in the absence of shearing via an empirical formula. A shear-dependent grain multiplication factor was deduced. The alloy exhibited a shear-thinning behavior where the viscosity obeyed the power law with a constant and an exponent of 0.9264 and 0.468, respectively. Moreover, the measured data were fitted to several proposed viscosity models and the model of Hirai et al. showed the best fit; therefore, it was recommended for predicting the viscosity of semisolid slurries. |
| first_indexed | 2024-03-10T22:54:15Z |
| format | Article |
| id | doaj.art-70cbddf72af5400aab23f985dfc87f3f |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-10T22:54:15Z |
| publishDate | 2023-09-01 |
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| record_format | Article |
| series | Crystals |
| spelling | doaj.art-70cbddf72af5400aab23f985dfc87f3f2023-11-19T10:09:25ZengMDPI AGCrystals2073-43522023-09-01139134510.3390/cryst13091345Analysis of the Effect of Simultaneous Melt Shearing and Cooling on Grain Formation and Rheology of A356 Aluminum AlloyMahmoud Ahmadein0Naser A. Alsaleh1Mahmoud Ahmed Elsayed2Sabbah Ataya3Department of Production Engineering and Mechanical Design, Tanta University, Tanta 31733, EgyptMechanical Engineering Department, Imam Mohammad Ibn Saud Islamic University, Riyadh 11564, Saudi ArabiaDepartment of Industrial and Management Engineering, Arab Academy for Science, Technology and Maritime Transport, Alexandria 21599, EgyptMechanical Engineering Department, Imam Mohammad Ibn Saud Islamic University, Riyadh 11564, Saudi ArabiaDespite the dozens of earlier research verifications, the contribution of shearing of molten metallic alloys during their solidification to grain formation is still ambiguous. Also, modeling of this phenomenon has received very little attention. Experiments were conducted in this study to investigate the effect of the shear rate on the density, size, and shape factor of the formed grains up to a solid fraction of 0.15 for the solidifying A356 aluminum alloy in the coaxial cylinder viscometer. The rheology of the formed semisolid slurry was studied as well. Results exhibited morphological evolution and grain refinement. The grain number density increased from 5 × 10<sup>8</sup> m<sup>−3</sup> in the absence of melt shearing to reach 4 × 10<sup>9</sup> m<sup>−3</sup> at the shear rate of 250 s<sup>−1</sup>. Also, the shape factor was improved to reach 0.78. Based on the experimental investigations, the grain number density under shearing was correlated to the shear rate and the grain number density in the absence of shearing via an empirical formula. A shear-dependent grain multiplication factor was deduced. The alloy exhibited a shear-thinning behavior where the viscosity obeyed the power law with a constant and an exponent of 0.9264 and 0.468, respectively. Moreover, the measured data were fitted to several proposed viscosity models and the model of Hirai et al. showed the best fit; therefore, it was recommended for predicting the viscosity of semisolid slurries.https://www.mdpi.com/2073-4352/13/9/1345semisolidgrain refinementshear raterheologygrain refinementaluminum alloys |
| spellingShingle | Mahmoud Ahmadein Naser A. Alsaleh Mahmoud Ahmed Elsayed Sabbah Ataya Analysis of the Effect of Simultaneous Melt Shearing and Cooling on Grain Formation and Rheology of A356 Aluminum Alloy Crystals semisolid grain refinement shear rate rheology grain refinement aluminum alloys |
| title | Analysis of the Effect of Simultaneous Melt Shearing and Cooling on Grain Formation and Rheology of A356 Aluminum Alloy |
| title_full | Analysis of the Effect of Simultaneous Melt Shearing and Cooling on Grain Formation and Rheology of A356 Aluminum Alloy |
| title_fullStr | Analysis of the Effect of Simultaneous Melt Shearing and Cooling on Grain Formation and Rheology of A356 Aluminum Alloy |
| title_full_unstemmed | Analysis of the Effect of Simultaneous Melt Shearing and Cooling on Grain Formation and Rheology of A356 Aluminum Alloy |
| title_short | Analysis of the Effect of Simultaneous Melt Shearing and Cooling on Grain Formation and Rheology of A356 Aluminum Alloy |
| title_sort | analysis of the effect of simultaneous melt shearing and cooling on grain formation and rheology of a356 aluminum alloy |
| topic | semisolid grain refinement shear rate rheology grain refinement aluminum alloys |
| url | https://www.mdpi.com/2073-4352/13/9/1345 |
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