Microstructural Evolution and Element Partitioning in the Phase Transformation of Ti-17 Alloy under Continuous Heating and Cooling Conditions
The microstructural evolution and alloying element partitioning in the α + β ↔ β phase transformation of Ti-17 alloy were explored under continuous heating and cooling conditions using the dilatometric method. Scanning electron microscopy and transmission electron microscopy were used to evaluate mi...
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MDPI AG
2020-08-01
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| author | Xudong An Xin Cai Mingpan Wan Min Lei Chaowen Huang Fei Zhao Fang Huang |
| author_facet | Xudong An Xin Cai Mingpan Wan Min Lei Chaowen Huang Fei Zhao Fang Huang |
| author_sort | Xudong An |
| collection | DOAJ |
| description | The microstructural evolution and alloying element partitioning in the α + β ↔ β phase transformation of Ti-17 alloy were explored under continuous heating and cooling conditions using the dilatometric method. Scanning electron microscopy and transmission electron microscopy were used to evaluate microstructural characteristics and trace alloying element partitioning behaviors occurring at different temperatures during heating and cooling. Results showed that the finer needle-like α phase first dissolved into the β phase in the matrix with increasing temperature, while the grain boundary α phase first coarsened and then transformed gradually into β phase during continuous heating. The dissolution of α phase of the alloy with the alloying element partitioning during continuous heating was observed. On the contrary, α<sub>GB</sub> formed at the prior β grain of the alloy during continuous cooling, which might be the nuclei of α colony, thus resulting in the formation of α colony in the matrix. As the temperature decreased, the elements’ concentrations in the α and β phases became increasingly varied due to element partition. Moreover, Al and Cr, which had higher diffusion coefficients than Mo, easily reached the concentration equilibrium of alloying elements in the α and β phases, respectively. The shrinkage of dilatometric curves during heating in the Ti-17 alloy are mainly attributed to the change of α-HCP (hexagonal close-packed) lattice to β-BCC (body-centered cubic) lattice; while the element partitioning during the β → α + β transformation plays an important role in the shrinkage of the dilatometric curves of the Ti-17 alloy during cooling. |
| first_indexed | 2024-03-10T17:57:25Z |
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| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-10T17:57:25Z |
| publishDate | 2020-08-01 |
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| spelling | doaj.art-de75bcef202e4818911a14b2bb5745532023-11-20T09:09:43ZengMDPI AGMetals2075-47012020-08-01108105410.3390/met10081054Microstructural Evolution and Element Partitioning in the Phase Transformation of Ti-17 Alloy under Continuous Heating and Cooling ConditionsXudong An0Xin Cai1Mingpan Wan2Min Lei3Chaowen Huang4Fei Zhao5Fang Huang6College of Materials and metallurgy, Guizhou University, Guiyang 550025, ChinaCollege of Materials and metallurgy, Guizhou University, Guiyang 550025, ChinaCollege of Materials and metallurgy, Guizhou University, Guiyang 550025, ChinaCollege of Materials and metallurgy, Guizhou University, Guiyang 550025, ChinaCollege of Materials and metallurgy, Guizhou University, Guiyang 550025, ChinaCollege of Materials and metallurgy, Guizhou University, Guiyang 550025, ChinaSchool of Aerospace Engineering, Guizhou Institute of Technology, Guiyang 550003, ChinaThe microstructural evolution and alloying element partitioning in the α + β ↔ β phase transformation of Ti-17 alloy were explored under continuous heating and cooling conditions using the dilatometric method. Scanning electron microscopy and transmission electron microscopy were used to evaluate microstructural characteristics and trace alloying element partitioning behaviors occurring at different temperatures during heating and cooling. Results showed that the finer needle-like α phase first dissolved into the β phase in the matrix with increasing temperature, while the grain boundary α phase first coarsened and then transformed gradually into β phase during continuous heating. The dissolution of α phase of the alloy with the alloying element partitioning during continuous heating was observed. On the contrary, α<sub>GB</sub> formed at the prior β grain of the alloy during continuous cooling, which might be the nuclei of α colony, thus resulting in the formation of α colony in the matrix. As the temperature decreased, the elements’ concentrations in the α and β phases became increasingly varied due to element partition. Moreover, Al and Cr, which had higher diffusion coefficients than Mo, easily reached the concentration equilibrium of alloying elements in the α and β phases, respectively. The shrinkage of dilatometric curves during heating in the Ti-17 alloy are mainly attributed to the change of α-HCP (hexagonal close-packed) lattice to β-BCC (body-centered cubic) lattice; while the element partitioning during the β → α + β transformation plays an important role in the shrinkage of the dilatometric curves of the Ti-17 alloy during cooling.https://www.mdpi.com/2075-4701/10/8/1054Ti-17 alloymicrostructural evolutionelement partitioningheating and cooling |
| spellingShingle | Xudong An Xin Cai Mingpan Wan Min Lei Chaowen Huang Fei Zhao Fang Huang Microstructural Evolution and Element Partitioning in the Phase Transformation of Ti-17 Alloy under Continuous Heating and Cooling Conditions Metals Ti-17 alloy microstructural evolution element partitioning heating and cooling |
| title | Microstructural Evolution and Element Partitioning in the Phase Transformation of Ti-17 Alloy under Continuous Heating and Cooling Conditions |
| title_full | Microstructural Evolution and Element Partitioning in the Phase Transformation of Ti-17 Alloy under Continuous Heating and Cooling Conditions |
| title_fullStr | Microstructural Evolution and Element Partitioning in the Phase Transformation of Ti-17 Alloy under Continuous Heating and Cooling Conditions |
| title_full_unstemmed | Microstructural Evolution and Element Partitioning in the Phase Transformation of Ti-17 Alloy under Continuous Heating and Cooling Conditions |
| title_short | Microstructural Evolution and Element Partitioning in the Phase Transformation of Ti-17 Alloy under Continuous Heating and Cooling Conditions |
| title_sort | microstructural evolution and element partitioning in the phase transformation of ti 17 alloy under continuous heating and cooling conditions |
| topic | Ti-17 alloy microstructural evolution element partitioning heating and cooling |
| url | https://www.mdpi.com/2075-4701/10/8/1054 |
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