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Precipitation of Carbides and Dissolution of Widmanstätten Structure for Enhanced Hardness in Ti 2 AlNb-Based Alloys

Journal Article


Abstract


  • Carbide-reinforced Ti 2 AlNb matrix composites were spark plasma sintered at 1100 °C by incorporating CNTs into single-B2-phase Ti-22Al-25Nb powders. The as-SPSed alloys were solution treated and then aged in different phase regions. By kinetics analysis and energy-dispersive spectroscopy, it is found carbon will stabilize α 2 phase during solution treatment, and the formation of carbide results in the Nb-depleted regions, which further induces the formation of curly B2 + O Widmanstätten structure during quenching. Different from the general Widmanstätten structure in the aged Ti 2 AlNb alloy, the remained α 2 will consume the B2 within the Widmanstätten structure, when the carbon-added alloy is aged in B2 + O phase region. Compared to the alloy without CNTs, the Vickers hardness of the aged carbon-added Ti 2 AlNb alloy is increased significantly, which is related to the uniform and abundant columnar carbides within the O-phase matrix.

Publication Date


  • 2019

Citation


  • Zhang, Y., Cai, Q., Liu, Y., Guo, Q., & Li, H. (2019). Precipitation of Carbides and Dissolution of Widmanstätten Structure for Enhanced Hardness in Ti 2 AlNb-Based Alloys. Journal of Materials Engineering and Performance, 28(3), 1892-1901. doi:10.1007/s11665-019-03965-9

Scopus Eid


  • 2-s2.0-85062662557

Web Of Science Accession Number


Start Page


  • 1892

End Page


  • 1901

Volume


  • 28

Issue


  • 3

Abstract


  • Carbide-reinforced Ti 2 AlNb matrix composites were spark plasma sintered at 1100 °C by incorporating CNTs into single-B2-phase Ti-22Al-25Nb powders. The as-SPSed alloys were solution treated and then aged in different phase regions. By kinetics analysis and energy-dispersive spectroscopy, it is found carbon will stabilize α 2 phase during solution treatment, and the formation of carbide results in the Nb-depleted regions, which further induces the formation of curly B2 + O Widmanstätten structure during quenching. Different from the general Widmanstätten structure in the aged Ti 2 AlNb alloy, the remained α 2 will consume the B2 within the Widmanstätten structure, when the carbon-added alloy is aged in B2 + O phase region. Compared to the alloy without CNTs, the Vickers hardness of the aged carbon-added Ti 2 AlNb alloy is increased significantly, which is related to the uniform and abundant columnar carbides within the O-phase matrix.

Publication Date


  • 2019

Citation


  • Zhang, Y., Cai, Q., Liu, Y., Guo, Q., & Li, H. (2019). Precipitation of Carbides and Dissolution of Widmanstätten Structure for Enhanced Hardness in Ti 2 AlNb-Based Alloys. Journal of Materials Engineering and Performance, 28(3), 1892-1901. doi:10.1007/s11665-019-03965-9

Scopus Eid


  • 2-s2.0-85062662557

Web Of Science Accession Number


Start Page


  • 1892

End Page


  • 1901

Volume


  • 28

Issue


  • 3