Influence of Laser Welding Speed on the Morphology and Phases Occurring in Spray-Compacted Hypereutectic Al-Si-Alloys
Normally, the weldability of aluminum alloys is ruled by the temperature range of solidification of an alloy according to its composition by the formation of hot cracks due to thermal shrinkage. However, for materials at nonequilibrium conditions, advantage can be taken by multiple phase formation,...
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MDPI AG
2016-11-01
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| Series: | Metals |
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| Online Access: | http://www.mdpi.com/2075-4701/6/12/295 |
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| author | Thomas Gietzelt Torsten Wunsch Florian Messerschmidt Holger Geßwein Uta Gerhards |
| author_facet | Thomas Gietzelt Torsten Wunsch Florian Messerschmidt Holger Geßwein Uta Gerhards |
| author_sort | Thomas Gietzelt |
| collection | DOAJ |
| description | Normally, the weldability of aluminum alloys is ruled by the temperature range of solidification of an alloy according to its composition by the formation of hot cracks due to thermal shrinkage. However, for materials at nonequilibrium conditions, advantage can be taken by multiple phase formation, leading to an annihilation of temperature stress at the microscopic scale, preventing hot cracks even for alloys with extreme melting range. In this paper, several spray-compacted hypereutectic aluminum alloys were laser welded. Besides different silicon contents, additional alloying elements like copper, iron and nickel were present in some alloys, affecting the microstructure. The microstructure was investigated at the delivery state of spray-compacted material as well as for a wide range of welding speeds ranging from 0.5 to 10 m/min, respectively. The impact of speed on phase composition and morphology was studied at different disequilibrium solidification conditions. At high welding velocity, a close-meshed network of eutectic Al-Si-composition was observed, whereas the matrix is filled with nearly pure aluminum, helping to diminish the thermal stress during accelerated solidification. Primary solidified silicon was found, however, containing considerable amounts of aluminum, which was not expected from phase diagrams obtained at the thermodynamic equilibrium. |
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| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-12-20T20:38:15Z |
| publishDate | 2016-11-01 |
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| spelling | doaj.art-50a16a25877647d2bbd1e472778a29c02022-12-21T19:27:10ZengMDPI AGMetals2075-47012016-11-0161229510.3390/met6120295met6120295Influence of Laser Welding Speed on the Morphology and Phases Occurring in Spray-Compacted Hypereutectic Al-Si-AlloysThomas Gietzelt0Torsten Wunsch1Florian Messerschmidt2Holger Geßwein3Uta Gerhards4Karlsruhe Institute of Technology, Institute for Micro Process Engineering, P.O. Box 3640, 76021 Karlsruhe, GermanyKarlsruhe Institute of Technology, Institute for Micro Process Engineering, P.O. Box 3640, 76021 Karlsruhe, GermanyKarlsruhe Institute of Technology, Institute for Micro Process Engineering, P.O. Box 3640, 76021 Karlsruhe, GermanyKarlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, 76021 Karlsruhe, GermanyKarlsruhe Institute of Technology, Institute for Micro Process Engineering, P.O. Box 3640, 76021 Karlsruhe, GermanyNormally, the weldability of aluminum alloys is ruled by the temperature range of solidification of an alloy according to its composition by the formation of hot cracks due to thermal shrinkage. However, for materials at nonequilibrium conditions, advantage can be taken by multiple phase formation, leading to an annihilation of temperature stress at the microscopic scale, preventing hot cracks even for alloys with extreme melting range. In this paper, several spray-compacted hypereutectic aluminum alloys were laser welded. Besides different silicon contents, additional alloying elements like copper, iron and nickel were present in some alloys, affecting the microstructure. The microstructure was investigated at the delivery state of spray-compacted material as well as for a wide range of welding speeds ranging from 0.5 to 10 m/min, respectively. The impact of speed on phase composition and morphology was studied at different disequilibrium solidification conditions. At high welding velocity, a close-meshed network of eutectic Al-Si-composition was observed, whereas the matrix is filled with nearly pure aluminum, helping to diminish the thermal stress during accelerated solidification. Primary solidified silicon was found, however, containing considerable amounts of aluminum, which was not expected from phase diagrams obtained at the thermodynamic equilibrium.http://www.mdpi.com/2075-4701/6/12/295hypereutectic aluminum alloyDISPALlaser weldingnonequilibrium solidification |
| spellingShingle | Thomas Gietzelt Torsten Wunsch Florian Messerschmidt Holger Geßwein Uta Gerhards Influence of Laser Welding Speed on the Morphology and Phases Occurring in Spray-Compacted Hypereutectic Al-Si-Alloys Metals hypereutectic aluminum alloy DISPAL laser welding nonequilibrium solidification |
| title | Influence of Laser Welding Speed on the Morphology and Phases Occurring in Spray-Compacted Hypereutectic Al-Si-Alloys |
| title_full | Influence of Laser Welding Speed on the Morphology and Phases Occurring in Spray-Compacted Hypereutectic Al-Si-Alloys |
| title_fullStr | Influence of Laser Welding Speed on the Morphology and Phases Occurring in Spray-Compacted Hypereutectic Al-Si-Alloys |
| title_full_unstemmed | Influence of Laser Welding Speed on the Morphology and Phases Occurring in Spray-Compacted Hypereutectic Al-Si-Alloys |
| title_short | Influence of Laser Welding Speed on the Morphology and Phases Occurring in Spray-Compacted Hypereutectic Al-Si-Alloys |
| title_sort | influence of laser welding speed on the morphology and phases occurring in spray compacted hypereutectic al si alloys |
| topic | hypereutectic aluminum alloy DISPAL laser welding nonequilibrium solidification |
| url | http://www.mdpi.com/2075-4701/6/12/295 |
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