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Precipitation behavior of Widmanstätten O phase associated with interface in aged Ti2AlNb-based alloys

Journal Article


Abstract


  • Ti2AlNb-based alloys, spark plasma sintered from ball-milled octahedral Ti-22Al-25Nb powder, are aged for 0–3 h in this study. Ball milling tunes the morphology of primary orthorhombic (O) phase to be columnar, and improves the mechanical properties of the alloys. The evolution of the Widmanstätten O phase, which brought main precipitation strengthening effect, is then investigated during the ageing process. The hardness of the alloys is improved by an increasing content of O phase and the reduced width of the Widmanstätten O phase; in addition, the length of Widmanstätten O phase also brings positive effect on the hardness, which indicates that the hardness is strongly coupled with the interface of the Widmanstätten O precipitates and B2 matrix. By means of transmission electron microscopy observation, the precipitation of O initials with an amorphous state, followed by a coherent interface between (110)B2 and (002)O, which is destroyed to be semi-coherent and incoherent during the next ageing stage.

Publication Date


  • 2018

Citation


  • Cai, Q., Li, M., Zhang, Y., Liu, Y., Ma, Z., Li, C., & Li, H. (2018). Precipitation behavior of Widmanstätten O phase associated with interface in aged Ti2AlNb-based alloys. Materials Characterization, 145, 413-422. doi:10.1016/j.matchar.2018.09.009

Scopus Eid


  • 2-s2.0-85052929010

Web Of Science Accession Number


Start Page


  • 413

End Page


  • 422

Volume


  • 145

Abstract


  • Ti2AlNb-based alloys, spark plasma sintered from ball-milled octahedral Ti-22Al-25Nb powder, are aged for 0–3 h in this study. Ball milling tunes the morphology of primary orthorhombic (O) phase to be columnar, and improves the mechanical properties of the alloys. The evolution of the Widmanstätten O phase, which brought main precipitation strengthening effect, is then investigated during the ageing process. The hardness of the alloys is improved by an increasing content of O phase and the reduced width of the Widmanstätten O phase; in addition, the length of Widmanstätten O phase also brings positive effect on the hardness, which indicates that the hardness is strongly coupled with the interface of the Widmanstätten O precipitates and B2 matrix. By means of transmission electron microscopy observation, the precipitation of O initials with an amorphous state, followed by a coherent interface between (110)B2 and (002)O, which is destroyed to be semi-coherent and incoherent during the next ageing stage.

Publication Date


  • 2018

Citation


  • Cai, Q., Li, M., Zhang, Y., Liu, Y., Ma, Z., Li, C., & Li, H. (2018). Precipitation behavior of Widmanstätten O phase associated with interface in aged Ti2AlNb-based alloys. Materials Characterization, 145, 413-422. doi:10.1016/j.matchar.2018.09.009

Scopus Eid


  • 2-s2.0-85052929010

Web Of Science Accession Number


Start Page


  • 413

End Page


  • 422

Volume


  • 145