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Development of α-phase morphologies during low temperature isothermal heat treatment of a Ti–5Al–5Mo–5V–3Cr alloy

Journal Article


Abstract


  • Development of different morphologies of the α-phase and their influence on the mechanical properties during low temperature isothermal aging of the near-β titanium alloy Ti–5Al–5Mo–5V–3Cr (Ti-5553) have been studied. A wide variety of different morphologies of the α-phase resulted from variations of the isothermal temperature and/or time. While after aging at 673 K or higher, a Widmanstätten star-shape was the dominant morphology of the α-phase, aging at lower temperatures resulted in the formation of triangular-shaped precipitate morphology. The first α-phase nucleated after 10 min isothermal holding time at 673 K, and the volume fraction increased to more than 80% after 8 h of holding time. This increase in the volume fraction of the α-phase caused an increase in the micro-hardness of the bulk material. X-ray diffraction and microstructural analyses provided evidence of ω-assisted nucleation of the α-phase. It is proposed that this mechanism by which the α-phase nucleates on pre-existing ω-phase particles account for the formation of the very large number of small α-particles that precipitated in the β-matrix.

Publication Date


  • 2011

Citation


  • Dehghan-Manshadi, A. & Dippenaar, R. J. (2011). Development of α-phase morphologies during low temperature isothermal heat treatment of a Ti–5Al–5Mo–5V–3Cr alloy. Materials Science and Engineering A: Structural Materials: Properties, Microstructure and Processing, 528 (3), 1833-1839.

Scopus Eid


  • 2-s2.0-78650172033

Ro Metadata Url


  • http://ro.uow.edu.au/engpapers/4622

Number Of Pages


  • 6

Start Page


  • 1833

End Page


  • 1839

Volume


  • 528

Issue


  • 3

Abstract


  • Development of different morphologies of the α-phase and their influence on the mechanical properties during low temperature isothermal aging of the near-β titanium alloy Ti–5Al–5Mo–5V–3Cr (Ti-5553) have been studied. A wide variety of different morphologies of the α-phase resulted from variations of the isothermal temperature and/or time. While after aging at 673 K or higher, a Widmanstätten star-shape was the dominant morphology of the α-phase, aging at lower temperatures resulted in the formation of triangular-shaped precipitate morphology. The first α-phase nucleated after 10 min isothermal holding time at 673 K, and the volume fraction increased to more than 80% after 8 h of holding time. This increase in the volume fraction of the α-phase caused an increase in the micro-hardness of the bulk material. X-ray diffraction and microstructural analyses provided evidence of ω-assisted nucleation of the α-phase. It is proposed that this mechanism by which the α-phase nucleates on pre-existing ω-phase particles account for the formation of the very large number of small α-particles that precipitated in the β-matrix.

Publication Date


  • 2011

Citation


  • Dehghan-Manshadi, A. & Dippenaar, R. J. (2011). Development of α-phase morphologies during low temperature isothermal heat treatment of a Ti–5Al–5Mo–5V–3Cr alloy. Materials Science and Engineering A: Structural Materials: Properties, Microstructure and Processing, 528 (3), 1833-1839.

Scopus Eid


  • 2-s2.0-78650172033

Ro Metadata Url


  • http://ro.uow.edu.au/engpapers/4622

Number Of Pages


  • 6

Start Page


  • 1833

End Page


  • 1839

Volume


  • 528

Issue


  • 3