Microstructure and mechanical properties of γ΄ strengthened Co–Ni–Al–W-base ODS alloys

Zhang, Lin; Qu, Xuanhui; Qin, Mingli; Rafi-Ud-Din, .; He, Xinbo; Liu, Y.

doi:10.1016/j.matchemphys.2012.06.055

Cited by 14 publications

(9 citation statements)

References 27 publications

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“…Hf increases the ´ stability and promotes its precipitation, also it could precipitate as oxide increasing the mechanical properties and the oxidation resistance, as it was mentioned previously. Following the previous discovers, the addition of Ni to this alloy [(10-50)Ni-10Al-7.5W-1Y2O3-1.5Hf-Co bal (at.%) [59]] increases the ´ volume fraction and the mechanical behaviour at high temperature as it is depict in Figure 1-14 and compared with a previous Zhang et al work [60].…”

Section: Powder Metallurgy Processingsupporting

confidence: 65%

“…In 2009, Zhang et al [70] added small amounts of Ti, Zr, Ca, Hf and Al to a Co-Y2O3-based ODS (Oxide dispersion strengthened) alloy by high-energy milling to disperse coherent or semi-coherent oxide nanoparticles uniformly throughout the matrix, thereby improving its high-temperature properties. These ODS alloys were characterized by hot compression and shown to be promising for high-temperature applications [59]; although the alloys produced by PM route could have less density, because of the porosity. Ameyama studied the density enhancement [71,72] in different alloys (Co-Cr-Mo, Ti-based…) with harmonic structure by PM route.…”

Section: Chapter 2: Motivation  Objectives mentioning

confidence: 99%

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Microstructure and compression strength of Co-based superalloys hardened by γ′ and carbide precipitation

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Freund

et al. 2018

Materials Science and Engineering: A

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El contenido de estas publicaciones ha sido incluido en esta tesis. Los capítulos en los que aparecen son el 1, 3, 4, 6 y 7 debido al uso de los datos para la explicación de los resultados obtenidos en diferentes apartados. Además, el material de estas fuentes incluido en la tesis no está señalado por medios tipográficos ni referencias. "On the role of processing parameters in sintered new Co-based (W,Al) alloys"

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Section: Powder Metallurgy Processingsupporting

confidence: 65%

Section: Chapter 2: Motivation  Objectives mentioning

confidence: 99%

Microstructure and compression strength of Co-based superalloys hardened by γ′ and carbide precipitation

Cartón-Cordero

Campos

Freund

et al. 2018

Materials Science and Engineering: A

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“…These alloys show uniform distribution of L1 2 -ordered c 0 precipitates with cuboidal morphology and Co 3 (Al, W) stoichiometry in a fcc c-Co matrix [9,10]. The morphologies and volume fractions of phases observed in the microstructures of these alloys are highly sensitive to alloying with elements like Ni, Ti, Mo, B, Cr, and Ta [11][12][13][14][15][16]. The thermodynamics and phase stability of the ordered c 0 structure have been studied using density functional theory (DFT) calculations by various groups [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Phase evolution and crystallography of precipitates during decomposition of new “tungsten-free” Co(Ni)–Mo–Al–Nb γ–γ′ superalloys at elevated temperatures

et al. 2016

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This article reports the microstructural stability and consequent phase decomposition including the appearance of topologically close-packed (TCP) phases at high temperature of recently discovered tungsten-free c-c 0 alloys of base composition Co-10Al-5Mo-2Nb with or without the addition of Ni and Ti. On prolonged aging at 800°C of the Co-10Al-5Mo-2Nb alloy, needle-shaped DO 19 -ordered precipitates with stoichiometry of Co 3 (Mo, Nb) start appearing in the microstructure. In addition, growth of cellular domains from the grain boundaries featuring a three-phase composite lamellar structure could be observed. These phases are fcc c-Co with composition different from the original matrix, CoAl with B2 ordering and Co 3 (Mo, Nb) with DO 19 ordering. All the phases exhibit well-defined crystallographic orientation relationships. The decomposition of the alloys depends on the solvus temperature of the c 0 phase. The Nicontaining alloy exhibits no phase decomposition until 100 h of aging at 800°C without any significant effect on c 0 volume fraction (76 %). However, at 950°C, the alloy decomposes leading to the appearance of four different phases including TCP phases: a Cr 3 Si-type cubic phase, a hexagonal Laves phase, rhombohedral l phase, and solid solution of Co phase. The c-c 0 microstructure in the Co-10Al-5Mo-2Nb and Co-30Ni-10Al-5Mo-2Ta alloys is not stable at 800 and 950°C, respectively, on long-term aging. This shows that the measured solvus temperatures (i.e., 866 and 990°C) are metastable solvus temperatures. We also report that the Ti-containing alloy exhibits superior stability with no evidence of either TCP phase formation or any other decomposition of c 0 precipitates, even after aging at 950°C for 100 h.

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“…Co-based oxide dispersion strengthened (ODS) alloys exhibit superior high-temperature mechanical properties, which is expected to fulfill the strict requirement in some hot-section components for aerospace and power-generation applications [1,2,3,4]. Co-Ni-W-based ODS alloy was designed by the combination of γ’ [Co 3 (Al,W)] precipitates and oxide dispersion.…”

Section: Introductionmentioning

confidence: 99%

“…Mechanical alloying (MA) is the main technique used to fabricate Co-based ODS alloy powder [1,2,3]. Owing to the extremely low solubility of Al and W in cobalt matrix at room temperature, mechanical alloying induced the formation of supersaturated solid solution but not the fully alloyed powder, resulting in the formation of a low volume fraction of γ’ precipitates [4,5,6,7]. Moreover, the problems of energy and time consumption, as well as the high tendency of aggregation, were experienced during the MA process [8].…”

Section: Introductionmentioning

confidence: 99%

Solution Synthesis of Co-Ni-W-Based ODS Alloy Powder

et al. 2019

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Low-temperature combustion synthesis was utilized to prepare Co-Ni-W-based oxide dispersion strengthened (ODS) alloy powder. The influence of the U/Co and C/Co ratios on the morphology and specific surface area of the combusted powder was investigated. Particle size, phase constituents, and element distribution of the resulting Co-Ni-W-based ODS alloy powder were characterized. The results indicate that insufficient urea induced no autocombustion reaction, while excess urea and glucose inhibited the combustion reaction. The optimized contents of urea and glucose were around U/Co = 1.2 and C/Co = 1.5, and the specific surface area of the powder reached 43.5 m2/g. The lamellar Co-Ni-W-based ODS alloy powder with particle sizes of 1–21 μm was the soft agglomeration of a high population of nanosized (65 nm) particles. These nanoparticles grew from 65 to 260 nm in the reduction temperature range of 700–900 °C. Homogeneous distribution of Co, Ni, W, and Y in the Co-Ni-W-based ODS alloy powder was achieved.

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Microstructure and mechanical properties of γ΄ strengthened Co–Ni–Al–W-base ODS alloys

Cited by 14 publications

References 27 publications

Microstructure and compression strength of Co-based superalloys hardened by γ′ and carbide precipitation

Microstructure and compression strength of Co-based superalloys hardened by γ′ and carbide precipitation

Phase evolution and crystallography of precipitates during decomposition of new “tungsten-free” Co(Ni)–Mo–Al–Nb γ–γ′ superalloys at elevated temperatures

Solution Synthesis of Co-Ni-W-Based ODS Alloy Powder

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