The formation of η-Ni3Ti phase microstructure in a cast nickel-based superalloy with high Ti/Al ratio
By over-aging at 900 °C and 1000 °C, a high volume-fraction of η-Ni3Ti phase was prepared in a cast nickel-based superalloy with high Ti/Al ratio. EBSD analysis shows that the η phase obeys a SN-type orientation relationship with γ matrix: <11 2‾ 0>η//<1 1‾ 0>γ, {0001}η//{111}γ. Four kin...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2024-03-01
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| Series: | Journal of Materials Research and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S223878542400156X |
| _version_ | 1797247908049846272 |
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| author | Kunlei Hou Meiqiong Ou Weiwei Xing Guangcai Ma Xianchao Hao Min Wang Yingche Ma |
| author_facet | Kunlei Hou Meiqiong Ou Weiwei Xing Guangcai Ma Xianchao Hao Min Wang Yingche Ma |
| author_sort | Kunlei Hou |
| collection | DOAJ |
| description | By over-aging at 900 °C and 1000 °C, a high volume-fraction of η-Ni3Ti phase was prepared in a cast nickel-based superalloy with high Ti/Al ratio. EBSD analysis shows that the η phase obeys a SN-type orientation relationship with γ matrix: <11 2‾ 0>η//<1 1‾ 0>γ, {0001}η//{111}γ. Four kinds of η phase variants with a 70.5° misorientation to each other are clarified. From the η/γ interface structure as detected by HRTEM, the thin plate-like morphology of η phase is attributed to the preferential growth of the incoherent {11 2‾ 0}η//{1 1‾ 0}γ interface. The formation of η phase at the grain boundary (GB) was by a discontinuous precipitation reaction, during which the original GB migrates from the η-nucleating side into the adjacent grain following the elongation of η phase to form a cellular structure. The detailed GB migration mechanism is investigated by EBSD and rationalized from the aspect of interface energy. For the formation of η phase in grain interior, three relative reactions are clarified: (i) MC+γ→M23C6+OA-γ′, OA-γ′→η, (ii) γ→M23C6+OA-γ′, OA-γ′→η, and (iii) γ′→OA-γ′, OA-γ′→η, where OA-γ′ is the newly precipitated γ′ phase during over-aging which shares a similar elemental distribution with η. The intermediate phase OA-γ′ is formed due to the comparably low nucleation barrier from γ while its subsequent transformation to η is excited by the higher thermodynamic stability of η as revealed by the calculation results by using the VASP software. At last, as conformed by STEM-HAADF, the structure transformation of OA-γ′→η is aided by the introduce of superlattice intrinsic stacking faults. |
| first_indexed | 2024-03-08T11:53:49Z |
| format | Article |
| id | doaj.art-edb281767cc94b17b50bca73e962003a |
| institution | Directory Open Access Journal |
| issn | 2238-7854 |
| language | English |
| last_indexed | 2024-04-24T20:06:10Z |
| publishDate | 2024-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj.art-edb281767cc94b17b50bca73e962003a2024-03-24T06:57:26ZengElsevierJournal of Materials Research and Technology2238-78542024-03-0129764778The formation of η-Ni3Ti phase microstructure in a cast nickel-based superalloy with high Ti/Al ratioKunlei Hou0Meiqiong Ou1Weiwei Xing2Guangcai Ma3Xianchao Hao4Min Wang5Yingche Ma6Shi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, ChinaShi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, ChinaShi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, ChinaShi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, ChinaShi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, ChinaShi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, ChinaCorresponding author. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.; Shi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, ChinaBy over-aging at 900 °C and 1000 °C, a high volume-fraction of η-Ni3Ti phase was prepared in a cast nickel-based superalloy with high Ti/Al ratio. EBSD analysis shows that the η phase obeys a SN-type orientation relationship with γ matrix: <11 2‾ 0>η//<1 1‾ 0>γ, {0001}η//{111}γ. Four kinds of η phase variants with a 70.5° misorientation to each other are clarified. From the η/γ interface structure as detected by HRTEM, the thin plate-like morphology of η phase is attributed to the preferential growth of the incoherent {11 2‾ 0}η//{1 1‾ 0}γ interface. The formation of η phase at the grain boundary (GB) was by a discontinuous precipitation reaction, during which the original GB migrates from the η-nucleating side into the adjacent grain following the elongation of η phase to form a cellular structure. The detailed GB migration mechanism is investigated by EBSD and rationalized from the aspect of interface energy. For the formation of η phase in grain interior, three relative reactions are clarified: (i) MC+γ→M23C6+OA-γ′, OA-γ′→η, (ii) γ→M23C6+OA-γ′, OA-γ′→η, and (iii) γ′→OA-γ′, OA-γ′→η, where OA-γ′ is the newly precipitated γ′ phase during over-aging which shares a similar elemental distribution with η. The intermediate phase OA-γ′ is formed due to the comparably low nucleation barrier from γ while its subsequent transformation to η is excited by the higher thermodynamic stability of η as revealed by the calculation results by using the VASP software. At last, as conformed by STEM-HAADF, the structure transformation of OA-γ′→η is aided by the introduce of superlattice intrinsic stacking faults.http://www.sciencedirect.com/science/article/pii/S223878542400156XNickel-based superalloyη-Ni3Ti phaseCrystallographic variantCellular precipitationPhase transformation |
| spellingShingle | Kunlei Hou Meiqiong Ou Weiwei Xing Guangcai Ma Xianchao Hao Min Wang Yingche Ma The formation of η-Ni3Ti phase microstructure in a cast nickel-based superalloy with high Ti/Al ratio Journal of Materials Research and Technology Nickel-based superalloy η-Ni3Ti phase Crystallographic variant Cellular precipitation Phase transformation |
| title | The formation of η-Ni3Ti phase microstructure in a cast nickel-based superalloy with high Ti/Al ratio |
| title_full | The formation of η-Ni3Ti phase microstructure in a cast nickel-based superalloy with high Ti/Al ratio |
| title_fullStr | The formation of η-Ni3Ti phase microstructure in a cast nickel-based superalloy with high Ti/Al ratio |
| title_full_unstemmed | The formation of η-Ni3Ti phase microstructure in a cast nickel-based superalloy with high Ti/Al ratio |
| title_short | The formation of η-Ni3Ti phase microstructure in a cast nickel-based superalloy with high Ti/Al ratio |
| title_sort | formation of η ni3ti phase microstructure in a cast nickel based superalloy with high ti al ratio |
| topic | Nickel-based superalloy η-Ni3Ti phase Crystallographic variant Cellular precipitation Phase transformation |
| url | http://www.sciencedirect.com/science/article/pii/S223878542400156X |
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