Alloy modification of γ-base titanium aluminide for improved oxidation resistance, creep strength and fracture toughness

Tsuyama, Seishi; Mitao, Shinji; Minakawa, Kuninori

doi:10.1016/b978-1-85166-822-9.50073-x

Cited by 11 publications

(14 citation statements)

References 4 publications

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“…It is reported that the formation of silicide particles results in a slight reduction in the a 2 -phase volume fraction [27,28]. Thus, the Si content needs to be reduced to improve both the tensile properties and the thermal stability of TiAl- Fig.…”

Section: Nominal Compositionmentioning

confidence: 97%

Effects of Si and C additions on the thermal stability of directionally solidified TiAl–Nb alloys

Kim

Lee

et al. 2005

Intermetallics

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Section: Nominal Compositionmentioning

confidence: 97%

Effects of Si and C additions on the thermal stability of directionally solidified TiAl–Nb alloys

Kim

Lee

et al. 2005

Intermetallics

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“…It is generally recognized that addition of Cr, Nb and Mn to TiAl alloys contribute toward increasing the ductility of TiAl, and Nb is also used for improving oxidation resistance [15,16,18]. In the case of C additions, some studies have shown that there existed two types of carbides in TiAl alloys, these are, the metastable P-type (perovskite) carbide phase precipitating in the g phase when aged at relatively low temperatures and the gradual dissolution of the Ptype carbides at temperatures higher than 750 C will include the growth of hexagonal (H-type) carbide [21,22]. The a 2 phase can dissolve carbon up to about 2 at%, whereas the g phase can dissolve less than about 0.5 at% [23].…”

Section: Deformation Behavior Tiealesiec Compositesmentioning

confidence: 99%

Comparison of titanium silicide and carbide reinforced in situ synthesized TiAl composites and their mechanical properties

Rao

Vyas

2011

Intermetallics

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“…Arrell et al [25] reported that, in the Ti-Al-Nb system, the precipitation of the silicide phase degraded both (␣ 2 ϩ ␥) TiAl alloys. [26] The improvement in creep properties has been attributed to pinning of dislocations by the titanium silicide particles or to the stabilization of the lamellar boundaries, so as to inhibit dynamic recrystallization. [26,27] To our knowledge, little work concerning the effects of Si additions on the properties of Ti 3 Al-based alloys with (␣ 2 ϩ B2 ϩ O) microstructures has been reported.…”

Section: Introductionmentioning

confidence: 99%

“…[26] The improvement in creep properties has been attributed to pinning of dislocations by the titanium silicide particles or to the stabilization of the lamellar boundaries, so as to inhibit dynamic recrystallization. [26,27] To our knowledge, little work concerning the effects of Si additions on the properties of Ti 3 Al-based alloys with (␣ 2 ϩ B2 ϩ O) microstructures has been reported. The objective of the present study is to incorporate a small fraction of the Ti 5 Si 3 phase into a Ti-24Al-14Nb-3V-0.5Mo alloy, with a view to improving its comprehensive properties.…”

Section: Introductionmentioning

confidence: 99%

A comparison study of microstructure and mechanical properties of Ti-24Al-14Nb-3V-0.5Mo with and without Si

Lü

Yang

Cui

et al. 2000

Metall Mater Trans A

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A comparative study has been made of the room-and elevated-temperature tensile properties, roomtemperature fracture toughness, fatigue-crack propagation rates, and 650 ЊC creep properties of Ti24Al-14Nb-3V-0.5Mo with and without 0.9 at. pct Si. Both alloys have microstructures consisting of the ␣ 2 , B2, and the orthorhombic O phase, with different proportions of the ␣ 2 phase relative to the (O ϩ B2) mixtures, depending on solution-treatment temperature. The alloy with a Si addition contains additional primary -Ti 5 Si 3 particles distributed in the (O ϩ B2) matrix. Tests of mechanical properties showed that the incorporation of a small fraction (about 0.03 by volume) of the Ti 5 Si 3 phase leads to greater room-temperature and elevated-temperature strengths, but lower room-temperature elongations and fracture toughness as compared with the base alloy. Alloys containing greater volume fractions of the ␣ 2 phase exhibited better tensile ductility, and this was attributed to the concurrent stabilization of the B2 phase. Examination of tensile-tested and fatigued specimens indicates that the primary failure mode of the alloys, regardless of Si addition, was due to the brittleness of the ␣ 2 phase; the silicide particles that debonded from the matrix also contribute to cracking in the monotonic loading mode. Up to a 20 pct improvement in creep-rupture life was observed in the Si-containing alloys, and this was interpreted in terms of the solute-strengthening effect of Si. While the incorporated Ti 5 Si 3 phase has an unfavorable effect on ductility and room-temperature fracture toughness, the difference in fatigue-crack propagation rates between the alloys with and without Si is minimal. It is concluded that the controlling factor for the fatigue failure in orthorhombic alloys is related to the (␣ 2 ϩ O ϩ B2) microstructure, instead of the Ti 5 Si 3 particles.

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Alloy modification of γ-base titanium aluminide for improved oxidation resistance, creep strength and fracture toughness

Cited by 11 publications

References 4 publications

Effects of Si and C additions on the thermal stability of directionally solidified TiAl–Nb alloys

Effects of Si and C additions on the thermal stability of directionally solidified TiAl–Nb alloys

Comparison of titanium silicide and carbide reinforced in situ synthesized TiAl composites and their mechanical properties

A comparison study of microstructure and mechanical properties of Ti-24Al-14Nb-3V-0.5Mo with and without Si

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