Bimodal microstructure dispersed with nanosized precipitates makes strong aluminum alloy with large ductility
A bimodal microstructure composed of large primary α-Al phases (PPs) and small secondarily solidified grains (SSGs) is fabricated in 6061 aluminum alloy by powder thixoforming (PTF) method after solution treatment. Artificial aging treatment introduces nanosized precipitates into the bimodal microst...
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| Format: | Article |
| Language: | English |
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Elsevier
2020-06-01
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| Series: | Materials & Design |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S026412752030229X |
| _version_ | 1818144534021799936 |
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| author | Xuezheng Zhang Tijun Chen |
| author_facet | Xuezheng Zhang Tijun Chen |
| author_sort | Xuezheng Zhang |
| collection | DOAJ |
| description | A bimodal microstructure composed of large primary α-Al phases (PPs) and small secondarily solidified grains (SSGs) is fabricated in 6061 aluminum alloy by powder thixoforming (PTF) method after solution treatment. Artificial aging treatment introduces nanosized precipitates into the bimodal microstructure, in which the number and growth rate of precipitates are different: the number in PPs is larger than that in SSGs due to the higher density of dislocations and lattice distortions in PPs, while the growth rate in SSGs is higher than that in PPs owing to the higher solute concentration in SSGs. As the number and size of precipitates are optimized in the bimodal microstructure, i.e., in peak-aged state, remarkable increments of 56.1% and 130.3% in ultimate tensile strength and yield strength while a moderate increase of 6.3% in ductility are achieved compared with the as-fabricated state, which overcomes the trade-off in strength and ductility of conventional aging-treated 6061 alloys with unimodal microstructure. The strengthening comes from the geometrically necessary dislocations induced by the deformation incompatibility of bimodal microstructure and from precipitate strengthening by nanosized precipitates, while the toughening is from the enhanced dislocation accumulation in this alloy. |
| first_indexed | 2024-12-11T11:49:05Z |
| format | Article |
| id | doaj.art-caea8d036044430d8a6af4d1a13b26b1 |
| institution | Directory Open Access Journal |
| issn | 0264-1275 |
| language | English |
| last_indexed | 2024-12-11T11:49:05Z |
| publishDate | 2020-06-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Materials & Design |
| spelling | doaj.art-caea8d036044430d8a6af4d1a13b26b12022-12-22T01:08:24ZengElsevierMaterials & Design0264-12752020-06-01191Bimodal microstructure dispersed with nanosized precipitates makes strong aluminum alloy with large ductilityXuezheng Zhang0Tijun Chen1State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, ChinaCorresponding author.; State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, ChinaA bimodal microstructure composed of large primary α-Al phases (PPs) and small secondarily solidified grains (SSGs) is fabricated in 6061 aluminum alloy by powder thixoforming (PTF) method after solution treatment. Artificial aging treatment introduces nanosized precipitates into the bimodal microstructure, in which the number and growth rate of precipitates are different: the number in PPs is larger than that in SSGs due to the higher density of dislocations and lattice distortions in PPs, while the growth rate in SSGs is higher than that in PPs owing to the higher solute concentration in SSGs. As the number and size of precipitates are optimized in the bimodal microstructure, i.e., in peak-aged state, remarkable increments of 56.1% and 130.3% in ultimate tensile strength and yield strength while a moderate increase of 6.3% in ductility are achieved compared with the as-fabricated state, which overcomes the trade-off in strength and ductility of conventional aging-treated 6061 alloys with unimodal microstructure. The strengthening comes from the geometrically necessary dislocations induced by the deformation incompatibility of bimodal microstructure and from precipitate strengthening by nanosized precipitates, while the toughening is from the enhanced dislocation accumulation in this alloy.http://www.sciencedirect.com/science/article/pii/S026412752030229X6061 aluminum alloyBimodal microstructureAging treatmentStrength-ductility trade-off |
| spellingShingle | Xuezheng Zhang Tijun Chen Bimodal microstructure dispersed with nanosized precipitates makes strong aluminum alloy with large ductility Materials & Design 6061 aluminum alloy Bimodal microstructure Aging treatment Strength-ductility trade-off |
| title | Bimodal microstructure dispersed with nanosized precipitates makes strong aluminum alloy with large ductility |
| title_full | Bimodal microstructure dispersed with nanosized precipitates makes strong aluminum alloy with large ductility |
| title_fullStr | Bimodal microstructure dispersed with nanosized precipitates makes strong aluminum alloy with large ductility |
| title_full_unstemmed | Bimodal microstructure dispersed with nanosized precipitates makes strong aluminum alloy with large ductility |
| title_short | Bimodal microstructure dispersed with nanosized precipitates makes strong aluminum alloy with large ductility |
| title_sort | bimodal microstructure dispersed with nanosized precipitates makes strong aluminum alloy with large ductility |
| topic | 6061 aluminum alloy Bimodal microstructure Aging treatment Strength-ductility trade-off |
| url | http://www.sciencedirect.com/science/article/pii/S026412752030229X |
| work_keys_str_mv | AT xuezhengzhang bimodalmicrostructuredispersedwithnanosizedprecipitatesmakesstrongaluminumalloywithlargeductility AT tijunchen bimodalmicrostructuredispersedwithnanosizedprecipitatesmakesstrongaluminumalloywithlargeductility |