Formation of β-Ti Phase in Multi-component Gamma Alloys

Kobayashi, Satoru; Takeyama, Masao; Motegi, Takahiro; Hirota, Noriaki; Matsuo, Takashi

doi:10.1557/proc-753-bb3.4

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…Moreover, the solid-state transformation pathway and the microstructure of TiAl-based alloys can be manipulated through β/β o phases [3,7,11]. According to reports by Cheng et al [12], Kobayashi et al [13], and Takeyama et al [14], a multitude of solid-state transformations and resulting microstructural morphologies can be achieved by stabilizing the β phase [3].…”

Section: Introductionmentioning

confidence: 99%

Experimental Phase Equilibria and Isopleth Section of 8Nb-TiAl Alloys

Liang

Song

et al. 2021

Metals

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The 8Nb isopleth section of a Ti-Al-Nb system is experimentally determined based on thermal analysis and thermodynamic calculation methods to obtain the phase transformation and equilibrium relations required for material design and fabrication. The phase transus and relations for the 8Nb-TiAl system show some deviations from the calculated thermodynamic results. The ordered βo phase transforms from the disordered β/α phases at 1200–1400 °C over a large Al concentration range, and this transformation is considered to be an intermediate type between the first- and second-order phase transitions. Moreover, the βo phases are retained at the ambient temperature in the 8Nb-TiAl microstructures. The ωo phase transforms from the highly ordered βo phase, rather than from α2 or βo with a low degree of atom ordering B2 (LOB2) structure, with Al concentration of 32–43 at% at approximately 850 °C. From the experimental detection, the transition of the ωo phase from the βo phase is considered to be a further ordering process.

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Section: Introductionmentioning

confidence: 99%

Experimental Phase Equilibria and Isopleth Section of 8Nb-TiAl Alloys

Liang

Song

et al. 2021

Metals

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show abstract

“…Moreover, the solid-state transformation pathway and the microstructure of TiAl-based alloys can be manipulated through β/βo phases [3,7,11]. According to reports by Cheng et al [12], Kobayashi et al [13], and Takeyama et al [14], a multitude of solid-state transformations and resulting microstructural morphologies can be achieved by stabilizing the β phase [3].…”

Section: Introductionmentioning

confidence: 99%

Experimental Phase Equilibria and Isopleth Section of 8Nb-TiAl Alloys

Xu¹,

Liang²,

Song³

et al. 2021

Preprint

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The 8Nb isopleth section of a Ti-Al-Nb system is experimentally determined based on thermal analysis and thermodynamic calculation methods to obtain the phase transformation and equilibrium relations required for material design and fabrication. The phase transus and relations for the 8Nb-TiAl system show some deviations from the calculated thermodynamic results. The ordered βo phase transforms from the disordered β/α phases at 1200–1400 °C over a large Al concentration range, and this transformation is considered to be an intermediate type between the first- and second-order phase transitions. Moreover, the βo phases are retained at the ambient temperature in the 8Nb-TiAl microstructures. The ωo phase transforms from the highly ordered βo phase, rather than from α2 or βo with low degree of atom ordering B2 (LOB2) structure, with Al concentration of 32–43 at.% at approximately 850 °C. From the experimental detection, the transition of the ωo phase from the βo phase is considered to be a further ordering process.

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“…Kobayashi et al revealed that the region to form the β phase region expands in Ti-45Al-(Nb, Mo)-(V, Cr) quaternary systems and suggested the existence of negative interaction between the Vth and VIth elements to stabilize the β phase [8]. Thus, in order to design the alloys with precisely controlled microstructures, the composition dependence of the phase stability should be clarified.…”

Section: Introductionmentioning

confidence: 99%

Phase Stability of β-Ti Phase in the TiAl Alloys with the Combined Addition of M Elements

Nakashima

Takeyama

2015

MRS Proc.

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Phase equilibria among the β-Ti, α-Ti and γ-TiAl phases were examined at 1473 K, in order to reveal the M/Nb ratio dependence of the relative phase stability of β phase in the Ti-AlNb-M (M: V, Cr, Mo) quaternary systems. In all of the quaternary systems, the expansion of β phase region toward the lower (Nb+M) content side is observed due to the existence of negative interaction to stabilize the β phase between the third and fourth elements (i.e. Nb-V, Nb-Cr and Nb-Mo). Composition dependence of the interaction is quantified as a function of the M/(Nb+M) ratio at 42 at.% Al. The strong interaction energy existing between the different group elements should be taken into account to design the multi-component TiAl alloys.

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Formation of β-Ti Phase in Multi-component Gamma Alloys

Cited by 5 publications

References 10 publications

Experimental Phase Equilibria and Isopleth Section of 8Nb-TiAl Alloys

Experimental Phase Equilibria and Isopleth Section of 8Nb-TiAl Alloys

Experimental Phase Equilibria and Isopleth Section of 8Nb-TiAl Alloys

Phase Stability of β-Ti Phase in the TiAl Alloys with the Combined Addition of M Elements

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