Effects of Cobalt in Nickel-Base Superalloys

Tien, J. K.; Jarrett, R. N.

doi:10.1007/978-94-009-7907-9_17

Cited by 5 publications

(3 citation statements)

References 13 publications

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“…By remaining in contact with the c channel, the supply of Cr and Co to the expanding SESF may be facilitated as Cr and Co preferentially partition to the c phase. [33][34][35][36] Other sources of excess Cr and Co could include nano-precipitates of c in the c¢.…”

Section: B Stacking Fault Shearmentioning

confidence: 99%

The Effect of Strain Rate on the Tensile Deformation Behavior of Single Crystal, Ni-Based Superalloys

Wang-Koh

Messé²,

Schwalbe

et al. 2023

Metall Mater Trans A

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Single crystal Nickel-based superalloys exhibit an anomalous yield point, the yield stress increasing with temperature to a maximum at around 750 ºC. Here, we demonstrate in the alloy CMSX-4 at 750 ºC that, although there is virtually no effect of strain rate on the initial yield point, at slow strain rates a second mechanism can initiate leading to a considerable softening effect. By examining the microstructures of a series of interrupted tests, this is attributed to the initiation of stacking fault shear after the operation of a secondary slip system. Using high-resolution TEM, the dislocation structures are shown to be identical in both structure and in the segregation of Co, Cr, and W, to those observed during creep deformation of single crystal alloys, although the conformation of the dislocations and faults differs from that observed during creep. This drop in flow stress at low strain rates is not observed in the alloys TMS138A and SRR99, in the former case, the improved creep resistance of this fourth-generation alloy would require a much slower strain rate to match the creep rate achievable at this temperature.

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Section: B Stacking Fault Shearmentioning

confidence: 99%

The Effect of Strain Rate on the Tensile Deformation Behavior of Single Crystal, Ni-Based Superalloys

Wang-Koh

Messé²,

Schwalbe

et al. 2023

Metall Mater Trans A

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“…Initially, work was conducted to determine a minimum Co content for achieving the required creep strain behavior and a T solvus value below 1165°C. A minimum Co content was sought to reduce the propensity for r formation [28], to promote improved resistance to type II hot corrosion damage since the melting temperature of Na 2 SO 4 -CoSO 4 eutectic is 565°C [29], compared to Na 2 SO 4 -NiSO 4 , which melts at 671°C [30], and to minimize raw material costs. The benefits of Co in lowering the stacking fault energy [28,31] and in producing more annealing twins are well documented [32].…”

Section: Alloy Designmentioning

confidence: 99%

“…A minimum Co content was sought to reduce the propensity for r formation [28], to promote improved resistance to type II hot corrosion damage since the melting temperature of Na 2 SO 4 -CoSO 4 eutectic is 565°C [29], compared to Na 2 SO 4 -NiSO 4 , which melts at 671°C [30], and to minimize raw material costs. The benefits of Co in lowering the stacking fault energy [28,31] and in producing more annealing twins are well documented [32]. The latter reduces effective grain size, which is important for fatigue crack nucleation life for coarse grain microstructures at temperatures below 650°C.…”

Section: Alloy Designmentioning

confidence: 99%

Developing Alloy Compositions for Future High Temperature Disk Rotors

Hardy

Argyrakis

Kitaguchi

et al. 2020

The Minerals, Metals &Amp; Materials Series

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Two new alloy compositions for possible disk rotor applications have been examined. Both were intended to have higher c 0 content than the existing alloy, RR1000, and be produced using powder metallurgy and isothermal forging to enable forgings to show a consistent coarse grain microstructure. Small pancake forgings of the new alloys and RR1000 were made and from these, blanks were cut, solution heat treated, cooled at measured rates and aged. Results of screening tests to understand the tensile, creep and dwell crack growth behavior, oxidation resistance and phase stability of these new alloys and coarse grain RR1000 are reported. The development alloys were similar in composition but exhibited different tensile and creep properties, phase stability and resistance to oxidation damage. Despite attempts to minimize variation in microstructure from heat treatment, differences in c 0 size distribution were found to influence tensile and creep behavior. One of the new alloys (Alloy 2) showed improved yield and tensile strength compared to RR1000. Alloy 2 displayed similar initial creep strain behavior to RR1000 but superior resistance to subsequent creep damage, producing longer creep rupture lives. All of the alloys showed crack retardation at low stress intensity factor ranges (DK) from 3600 s dwell cycles at 700°C in air. This occurred whilst crack growth was intergranular. Alloy 1 was found to precipitate C14 Laves phase from long term exposure at 800°C. Like RR1000, r phase was not detected in the new alloys after 750 h at 800°C.

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Effects of Cobalt on the Microstructures and Mechanical Properties of the Fe-Ni-Co-Base Superalloy Refractoloy26

Chen¹,

Zhuang²,

1987

High Temperature Alloys

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Effects of Cobalt in Nickel-Base Superalloys

Cited by 5 publications

References 13 publications

The Effect of Strain Rate on the Tensile Deformation Behavior of Single Crystal, Ni-Based Superalloys

The Effect of Strain Rate on the Tensile Deformation Behavior of Single Crystal, Ni-Based Superalloys

Developing Alloy Compositions for Future High Temperature Disk Rotors

Effects of Cobalt on the Microstructures and Mechanical Properties of the Fe-Ni-Co-Base Superalloy Refractoloy26

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