FATIGUE-CRACK GROWTH BEHAVIOR IN A DUAL-PHASE (γ+α2) TiAl INTERMETALLICALLOY AT ELEVATED TEMPERATURES

K. T. Venkateswara Rao; Y-W. Kim; R. O. Ritchie

FATIGUE-CRACK GROWTH BEHAVIOR IN A DUAL-PHASE (γ+α₂) TiAl INTERMETALLICALLOY AT ELEVATED TEMPERATURES

K. T. Venkateswara Rao, Y-W. Kim, R. O. Ritchie

Research output: Chapters, Conference Papers, Creative and Literary Works › RGC 32 - Refereed conference paper (with host publication) › peer-review

3 Citations (Scopus)

Abstract

Fatigue-crack propagation behavior in a Ti-47.3Al-2.3Nb-1.5Cr-0.4V (at.%) alloy is examined at 650 and 800°C in two markedly different microstructural conditions, namely a duplex (fine, equiaxed) and fully-lamellar (coarse, microlaminated) microstructures; results are compared with those obtained at room temperature. It is found that the lamellar microstructure exhibits increased fatigue resistance compared to the duplex structure at all temperatures, principally due to shielding from crack deflection, microcracking and shear-ligament bridging, although the effect of the bridging is progressively diminished under cyclic loads. The extent of improvement, however, is significantly lower during cyclic fatigue compared to monotonic fracture. For both (γ+α₂) microstructures, maximum resistance to fatigue-crack growth is seen at 800°C; growth rates, however, are faster at 650°C than at ambient temperatures. Such variations in fatigue resistance with test temperature are attributed to intrinsic differences in crack-tip deformation at 800°C and 650°C, that respectively correspond to temperatures above and below the ductile-to-brittle transition temperature for γ-TiAl (∼700°C).

Original language	English
Title of host publication	Gamma Titanium Aluminides
Subtitle of host publication	Proceedings of a symposium sponsored by the Structural Materials Division (SMD) of TMS held during the TMS '95 Annual Meeting
Editors	Young-Won Kim, Richard Wagner, Masaharu Yamaguchi
Publisher	Minerals, Metals & Materials Society
Pages	893-901
Publication status	Published - Feb 1995
Externally published	Yes
Event	1995 124th TMS Annual Meeting - Las Vegas, United States Duration: 13 Feb 1995 → 16 Feb 1995

Publication series

Name	TMS Annual Meeting

Conference

Conference	1995 124th TMS Annual Meeting
Country/Territory	United States
City	Las Vegas
Period	13/02/95 → 16/02/95

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Venkateswara Rao, K. T., Kim, Y.-W., & Ritchie, R. O. (1995). FATIGUE-CRACK GROWTH BEHAVIOR IN A DUAL-PHASE (γ+α₂) TiAl INTERMETALLICALLOY AT ELEVATED TEMPERATURES. In Y.-W. Kim, R. Wagner, & M. Yamaguchi (Eds.), Gamma Titanium Aluminides: Proceedings of a symposium sponsored by the Structural Materials Division (SMD) of TMS held during the TMS '95 Annual Meeting (pp. 893-901). (TMS Annual Meeting). Minerals, Metals & Materials Society.

Venkateswara Rao, K. T. ; Kim, Y-W. ; Ritchie, R. O. / FATIGUE-CRACK GROWTH BEHAVIOR IN A DUAL-PHASE (γ+α₂) TiAl INTERMETALLICALLOY AT ELEVATED TEMPERATURES. Gamma Titanium Aluminides: Proceedings of a symposium sponsored by the Structural Materials Division (SMD) of TMS held during the TMS '95 Annual Meeting. editor / Young-Won Kim ; Richard Wagner ; Masaharu Yamaguchi. Minerals, Metals & Materials Society, 1995. pp. 893-901 (TMS Annual Meeting).

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title = "FATIGUE-CRACK GROWTH BEHAVIOR IN A DUAL-PHASE (γ+α2) TiAl INTERMETALLICALLOY AT ELEVATED TEMPERATURES",

abstract = "Fatigue-crack propagation behavior in a Ti-47.3Al-2.3Nb-1.5Cr-0.4V (at.%) alloy is examined at 650 and 800°C in two markedly different microstructural conditions, namely a duplex (fine, equiaxed) and fully-lamellar (coarse, microlaminated) microstructures; results are compared with those obtained at room temperature. It is found that the lamellar microstructure exhibits increased fatigue resistance compared to the duplex structure at all temperatures, principally due to shielding from crack deflection, microcracking and shear-ligament bridging, although the effect of the bridging is progressively diminished under cyclic loads. The extent of improvement, however, is significantly lower during cyclic fatigue compared to monotonic fracture. For both (γ+α2) microstructures, maximum resistance to fatigue-crack growth is seen at 800°C; growth rates, however, are faster at 650°C than at ambient temperatures. Such variations in fatigue resistance with test temperature are attributed to intrinsic differences in crack-tip deformation at 800°C and 650°C, that respectively correspond to temperatures above and below the ductile-to-brittle transition temperature for γ-TiAl (∼700°C).",

author = "{Venkateswara Rao}, {K. T.} and Y-W. Kim and Ritchie, {R. O.}",

year = "1995",

month = feb,

language = "English",

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publisher = "Minerals, Metals & Materials Society",

pages = "893--901",

editor = "Young-Won Kim and Richard Wagner and Masaharu Yamaguchi",

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note = "1995 124th TMS Annual Meeting ; Conference date: 13-02-1995 Through 16-02-1995",

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Venkateswara Rao, KT, Kim, Y-W & Ritchie, RO 1995, FATIGUE-CRACK GROWTH BEHAVIOR IN A DUAL-PHASE (γ+α₂) TiAl INTERMETALLICALLOY AT ELEVATED TEMPERATURES. in Y-W Kim, R Wagner & M Yamaguchi (eds), Gamma Titanium Aluminides: Proceedings of a symposium sponsored by the Structural Materials Division (SMD) of TMS held during the TMS '95 Annual Meeting. TMS Annual Meeting, Minerals, Metals & Materials Society, pp. 893-901, 1995 124th TMS Annual Meeting, Las Vegas, Nevada, United States, 13/02/95.

FATIGUE-CRACK GROWTH BEHAVIOR IN A DUAL-PHASE (γ+α₂) TiAl INTERMETALLICALLOY AT ELEVATED TEMPERATURES. / Venkateswara Rao, K. T.; Kim, Y-W.; Ritchie, R. O.
Gamma Titanium Aluminides: Proceedings of a symposium sponsored by the Structural Materials Division (SMD) of TMS held during the TMS '95 Annual Meeting. ed. / Young-Won Kim; Richard Wagner; Masaharu Yamaguchi. Minerals, Metals & Materials Society, 1995. p. 893-901 (TMS Annual Meeting).

Research output: Chapters, Conference Papers, Creative and Literary Works › RGC 32 - Refereed conference paper (with host publication) › peer-review

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AU - Kim, Y-W.

AU - Ritchie, R. O.

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N2 - Fatigue-crack propagation behavior in a Ti-47.3Al-2.3Nb-1.5Cr-0.4V (at.%) alloy is examined at 650 and 800°C in two markedly different microstructural conditions, namely a duplex (fine, equiaxed) and fully-lamellar (coarse, microlaminated) microstructures; results are compared with those obtained at room temperature. It is found that the lamellar microstructure exhibits increased fatigue resistance compared to the duplex structure at all temperatures, principally due to shielding from crack deflection, microcracking and shear-ligament bridging, although the effect of the bridging is progressively diminished under cyclic loads. The extent of improvement, however, is significantly lower during cyclic fatigue compared to monotonic fracture. For both (γ+α2) microstructures, maximum resistance to fatigue-crack growth is seen at 800°C; growth rates, however, are faster at 650°C than at ambient temperatures. Such variations in fatigue resistance with test temperature are attributed to intrinsic differences in crack-tip deformation at 800°C and 650°C, that respectively correspond to temperatures above and below the ductile-to-brittle transition temperature for γ-TiAl (∼700°C).

AB - Fatigue-crack propagation behavior in a Ti-47.3Al-2.3Nb-1.5Cr-0.4V (at.%) alloy is examined at 650 and 800°C in two markedly different microstructural conditions, namely a duplex (fine, equiaxed) and fully-lamellar (coarse, microlaminated) microstructures; results are compared with those obtained at room temperature. It is found that the lamellar microstructure exhibits increased fatigue resistance compared to the duplex structure at all temperatures, principally due to shielding from crack deflection, microcracking and shear-ligament bridging, although the effect of the bridging is progressively diminished under cyclic loads. The extent of improvement, however, is significantly lower during cyclic fatigue compared to monotonic fracture. For both (γ+α2) microstructures, maximum resistance to fatigue-crack growth is seen at 800°C; growth rates, however, are faster at 650°C than at ambient temperatures. Such variations in fatigue resistance with test temperature are attributed to intrinsic differences in crack-tip deformation at 800°C and 650°C, that respectively correspond to temperatures above and below the ductile-to-brittle transition temperature for γ-TiAl (∼700°C).

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M3 - RGC 32 - Refereed conference paper (with host publication)

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PB - Minerals, Metals & Materials Society

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Venkateswara Rao KT, Kim YW, Ritchie RO. FATIGUE-CRACK GROWTH BEHAVIOR IN A DUAL-PHASE (γ+α₂) TiAl INTERMETALLICALLOY AT ELEVATED TEMPERATURES. In Kim YW, Wagner R, Yamaguchi M, editors, Gamma Titanium Aluminides: Proceedings of a symposium sponsored by the Structural Materials Division (SMD) of TMS held during the TMS '95 Annual Meeting. Minerals, Metals & Materials Society. 1995. p. 893-901. (TMS Annual Meeting).