Thermomechanical fatigue behavior of the third-generation, single-crystal superalloy TMS-75: Deformation structure

Zhou, Hao; Ro, Y.; Koizumi, Yutaka; Kobayashi, Toshiharu; Harada, Hiroshi; Okada, Ikuo

doi:10.1007/s11661-004-0086-8

Cited by 15 publications

(6 citation statements)

References 19 publications

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“…Ni-based superalloys exhibit the most outstanding mechanical properties (especially the creep-resistance), corrosion- and oxidation-resistant properties at elevated temperatures among all the conventional structural materials. Their excellent properties are benefited from their specially coherent microstructures of spherical or cuboidal L1 2 -γ′ nanoprecipitates into FCC-γ solid solution [ 4 , 5 , 6 ]. Especially the coherent precipitation of cuboidal L1 2 -γ′ particles in single-crystal superalloys is responsible for the necessary strength at much higher temperatures near to the melting point [ 40 , 41 ].…”

Section: Precipitate Morphology and Precipitation Strengthening Inmentioning

confidence: 99%

“…Precipitation strengthening with intermetallic compounds is the most effective approach for the enhancement of alloy strength in engineering structural materials, compared with solid-solution strengthening, grain-boundary strengthening, and work hardening [ 1 , 2 , 3 ]. Especially at high temperatures (HTs), the precipitation strengthening is indispensable due to the prominent long-time microstructural stabilities caused by second-phase precipitates in the solid-solution matrix [ 4 , 5 , 6 , 7 , 8 ]. Among them, the coherent ordered phases, such as L1 2 -Ni 3 Al ( cP 4-Cu 3 Au) of the face-centered-cubic (FCC) solid solution [ 4 , 5 ], and B2-NiAl ( cP 2-ClCs) of the body-centered-cubic (BCC) solid solution [ 9 , 10 , 11 , 12 , 13 ], are crucial for the HT creep-resistant properties of alloys due to the perfect coherency between the ordered phase and the solid-solution matrix.…”

Section: Introductionmentioning

confidence: 99%

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Coherent Precipitation and Strengthening in Compositionally Complex Alloys: A Review

Wang

Pang

et al. 2018

Entropy

131

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High-performance conventional engineering materials (including Al alloys, Mg alloys, Cu alloys, stainless steels, Ni superalloys, etc.) and newly-developed high entropy alloys are all compositionally-complex alloys (CCAs). In these CCA systems, the second-phase particles are generally precipitated in their solid-solution matrix, in which the precipitates are diverse and can result in different strengthening effects. The present work aims at generalizing the precipitation behavior and precipitation strengthening in CCAs comprehensively. First of all, the morphology evolution of second-phase particles and precipitation strengthening mechanisms are introduced. Then, the precipitation behaviors in diverse CCA systems are illustrated, especially the coherent precipitation. The relationship between the particle morphology and strengthening effectiveness is discussed. It is addressed that the challenge in the future is to design the stable coherent microstructure in different solid-solution matrices, which will be the most effective approach for the enhancement of alloy strength.

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Section: Precipitate Morphology and Precipitation Strengthening Inmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Coherent Precipitation and Strengthening in Compositionally Complex Alloys: A Review

Wang

Pang

et al. 2018

Entropy

131

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“…i) Temperature-strain phasing (IP or OP TMF) [24] ii) Maximum temperature extreme [21,25,28,29] iii) Minimum temperature extreme [21,25,28,29] iv) Mean Strain [30,31] v) Creep-fatigue interactions due to long dwells coupled with periodic TMF cycles [25,[32][33][34][35][36][37][38][39][40][41][42] vi) Elastic anisotropy due to crystal orientation [12,14,21,33,[43][44][45][46] vii) Over-aging of the microstructure during service conditions [18,[47][48][49][50].…”

Section: Introductionmentioning

confidence: 99%

Parameters influencing thermomechanical fatigue of a directionally-solidified Ni-base superalloy

Kirka

Brindley

Neu

et al. 2015

International Journal of Fatigue

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Thermomechanical fatigue (TMF) is a low cycle fatigue process in which material life is correlated to the mechanical strain amplitude. However, it is well known that several other factors influence this life. This paper examines several of these parameters and their influence on life using experiments conducted on a second generation directionally-solidified (DS) Ni-base superalloy. The parameters considered include the influence of the temperature extremums (T max of either 750 or 950 • C and T min of either 100 or 500 • C), strain ratio (R ), the strain-temperature phasing (in-phase (IP) and out-of-phase (OP)), the influence of dwells at the high temperature end of the cycle resulting in a creep-fatigue (CF) interaction, and material anisotropy associated with the grain growth direction (longitudinal versus transverse). Results suggest that the phasing has a primary role in controlling the mechanism of degradation. IP TMF is dominated by crack formation in volumes surrounding debonded carbides for both continuously cycling (CC) and CF at 950 and 750 • C, while OP TMF is dominated by surface oxidation and repetitive cracking of the oxide that reforms at the crack tip at 950 • C. Decreasing the T max to 750 • C the environmental and creep effects are reduced resulting in virtually pure fatigue exposure under OP conditions. With decreasing T min from 500 • C to 100 • C was observed an increase in inelastic strain amplitude and 1 corresponding decrease in life. Variations in R were found to have no significant influence on life or stabilized stress behavior. TMF loading in the transverse orientation resulted in life reductions over the longitudinal orientation due to cracks propagating in a transgranular manner. Lastly, only in material exposed to CF with a T max of 950 • C rafting of the γ precipitates was observed.

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“…Under thermo-mechanical fatigue (TMF), the number of cycles to failure of a single-crystal superalloy was found to decrease drastically with an increase of the compressive strain hold time [8]. The compressive creep strength of single-crystal superalloys is lower than the tensile creep strength on [001] loading [2]; therefore, high-tensile residual stress is produced by the larger stress relaxation during the compressive hold.…”

Section: Introductionmentioning

confidence: 99%

Tension/Compression Asymmetry in Yield and Creep Strengths of Ni-Based Superalloys

Tsuno¹,

Shimabayashi²,

Kakehi³

et al. 2008

Superalloys 2008 (Eleventh International Symposium)

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The tension/compression asymmetries of yield and creep strengths of three kinds of single-crystal superalloys-PWA1480, CMSX-4, and TMS-75-and a DS superalloy, Mar-M247LC, were investigated at intermediate and high temperatures. In PWA1480, tensile yield strength was higher than the compressive strength from 20°C to 750 °C. From the TEM observation, it was found that the asymmetry of yield strengths is primarily due to the microtwin formation associated with a superlattice extrinsic stacking fault (SESF). In CMSX-4 and TMS-75, tensile/compressive yield strengths were comparable at every temperature, and shearing of γ′ precipitates by a/2<110> dislocations pairs was the dominant deformation mechanism in both tensile and compressive tests at 750 °C. The creep response of these materials were quite different than their yielding response. CMSX-4 and TMS-75 showed distinctive creep tension/compression asymmetry. These two alloys showed large creep strain caused by {111}<112> slip at 750 °C under tensile stress, and mechanical twins at 750 °C and 900 °C under compressive stresses. Tension/compression asymmetry of CMSX-4 and TMS-75 was larger at 900 °C than at 750 °C because <112> viscous slip was not observed under tensile stress at 900 °C. The asymmetric nature of PWA1480 was small at both 750 °C and 900 °C because the dominant deformation mode in both tension and compression is a combination of both a/2<110> dislocation's bowing on the {111} plane in the matrix and climbing along the γ/γ′ interfaces.

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Thermomechanical fatigue behavior of the third-generation, single-crystal superalloy TMS-75: Deformation structure

Cited by 15 publications

References 19 publications

Coherent Precipitation and Strengthening in Compositionally Complex Alloys: A Review

Coherent Precipitation and Strengthening in Compositionally Complex Alloys: A Review

Parameters influencing thermomechanical fatigue of a directionally-solidified Ni-base superalloy

Tension/Compression Asymmetry in Yield and Creep Strengths of Ni-Based Superalloys

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