Microstructure evolution and room temperature deformation of a directionally solidified Nb-Si-Ti-Cr-Al-Hf-Y alloy
An Nb-14Si-22Ti-4Cr-2Al-2Hf-0.15Y(at.%) alloy was prepared by directional solidification (DS) with liquid metal cooling, and the withdrawal rates selected were 1.2, 6, and 18 mm·min-1, respectively. The Influence of withdrawal rate and heat treatment on the microstructural evolution, fracture toughn...
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Foundry Journal Agency
2013-11-01
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| Series: | China Foundry |
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| author | Wang Bin Jia Lina Yuan Sainan |
| author_facet | Wang Bin Jia Lina Yuan Sainan |
| author_sort | Wang Bin |
| collection | DOAJ |
| description | An Nb-14Si-22Ti-4Cr-2Al-2Hf-0.15Y(at.%) alloy was prepared by directional solidification (DS) with liquid metal cooling, and the withdrawal rates selected were 1.2, 6, and 18 mm·min-1, respectively. The Influence of withdrawal rate and heat treatment on the microstructural evolution, fracture toughness and tensile strength at room temperature were investigated. Results show that the directionally solidified microstructure is composed of primary (Nb, X)ss dendrites and (Nb, X)ss/α-(Nb, X)5Si3 eutectic cells aligning with the growth direction. The formation of bulk Nb3Si is suppressed. With an increase in withdrawal rate, the dendrite arm spacing of (Nb, X)ss decreases, and the (Nb, X)ss/α-(Nb, X)5Si3 eutectic cells become finer and distribute homogeneously. Directional solidification can significantly improve the room temperature fracture toughness, especially the alloy with a withdrawal rate of 6 mm·min-1; its average value reaches 14.1 MPa·m0.5, about 34% higher than that of the alloy without directional solidification. The withdrawal rate has obvious effect on tensile strength, and the tensile strength is improved from 200 MPa to 429 MPa as the withdrawal rate increases from 1.2 mm·min-1 to 1.8 mm·min-1. After heat treatment, the primary (Nb, X)ss branches become coarser; both the room temperature fracture toughness and tensile strength of the alloys solidified at 1.2 and 6 mm·min-1 are somewhat lower than the corresponding values of the alloy without heat treatment, while they are higher than the corresponding values of the alloy without heat treatment when solidified at 18 mm·min-1. |
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| spelling | doaj.art-454e3e76d7254baf866cf0353df8993d2022-12-22T00:44:17ZengFoundry Journal AgencyChina Foundry1672-64212013-11-01106345350Microstructure evolution and room temperature deformation of a directionally solidified Nb-Si-Ti-Cr-Al-Hf-Y alloyWang Bin0Jia Lina1Yuan Sainan2School of Materials Science and Engineering, Beihang University, Beijing 100191, ChinaSchool of Materials Science and Engineering, Beihang University, Beijing 100191, ChinaSchool of Materials Science and Engineering, Beihang University, Beijing 100191, ChinaAn Nb-14Si-22Ti-4Cr-2Al-2Hf-0.15Y(at.%) alloy was prepared by directional solidification (DS) with liquid metal cooling, and the withdrawal rates selected were 1.2, 6, and 18 mm·min-1, respectively. The Influence of withdrawal rate and heat treatment on the microstructural evolution, fracture toughness and tensile strength at room temperature were investigated. Results show that the directionally solidified microstructure is composed of primary (Nb, X)ss dendrites and (Nb, X)ss/α-(Nb, X)5Si3 eutectic cells aligning with the growth direction. The formation of bulk Nb3Si is suppressed. With an increase in withdrawal rate, the dendrite arm spacing of (Nb, X)ss decreases, and the (Nb, X)ss/α-(Nb, X)5Si3 eutectic cells become finer and distribute homogeneously. Directional solidification can significantly improve the room temperature fracture toughness, especially the alloy with a withdrawal rate of 6 mm·min-1; its average value reaches 14.1 MPa·m0.5, about 34% higher than that of the alloy without directional solidification. The withdrawal rate has obvious effect on tensile strength, and the tensile strength is improved from 200 MPa to 429 MPa as the withdrawal rate increases from 1.2 mm·min-1 to 1.8 mm·min-1. After heat treatment, the primary (Nb, X)ss branches become coarser; both the room temperature fracture toughness and tensile strength of the alloys solidified at 1.2 and 6 mm·min-1 are somewhat lower than the corresponding values of the alloy without heat treatment, while they are higher than the corresponding values of the alloy without heat treatment when solidified at 18 mm·min-1.http://www.foundryworld.com/uploadfile/2013121853016453.pdfNb-Si-Ti-Cr-Al-Hf-Ydirectional solidificationheat treatmentmechanical properties |
| spellingShingle | Wang Bin Jia Lina Yuan Sainan Microstructure evolution and room temperature deformation of a directionally solidified Nb-Si-Ti-Cr-Al-Hf-Y alloy China Foundry Nb-Si-Ti-Cr-Al-Hf-Y directional solidification heat treatment mechanical properties |
| title | Microstructure evolution and room temperature deformation of a directionally solidified Nb-Si-Ti-Cr-Al-Hf-Y alloy |
| title_full | Microstructure evolution and room temperature deformation of a directionally solidified Nb-Si-Ti-Cr-Al-Hf-Y alloy |
| title_fullStr | Microstructure evolution and room temperature deformation of a directionally solidified Nb-Si-Ti-Cr-Al-Hf-Y alloy |
| title_full_unstemmed | Microstructure evolution and room temperature deformation of a directionally solidified Nb-Si-Ti-Cr-Al-Hf-Y alloy |
| title_short | Microstructure evolution and room temperature deformation of a directionally solidified Nb-Si-Ti-Cr-Al-Hf-Y alloy |
| title_sort | microstructure evolution and room temperature deformation of a directionally solidified nb si ti cr al hf y alloy |
| topic | Nb-Si-Ti-Cr-Al-Hf-Y directional solidification heat treatment mechanical properties |
| url | http://www.foundryworld.com/uploadfile/2013121853016453.pdf |
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